Faculty Publications: July, 2013

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Title:
Manipulation of molecules with electromagnetic fields
Authors:
Lemeshko, Mikhail; Krems, Roman V.; Doyle, John M.; Kais, Sabre
Publication:
Molecular Physics, vol. 111, issue 12-13, pp. 1648-1682
Publication Date:
07/2013
Origin:
CROSSREF
DOI:
10.1080/00268976.2013.813595
Bibliographic Code:
2013MolPh.111.1648L

Abstract

The goal of the present article is to review the major developments that have led to the current understanding of molecule-field interactions and experimental methods for manipulating molecules with electromagnetic fields. Molecule-field interactions are at the core of several, seemingly distinct, areas of molecular physics. This is reflected in the organization of this article, which includes sections on Field control of molecular beams, External field traps for cold molecules, Control of molecular orientation and molecular alignment, Manipulation of molecules by non-conservative forces, Ultracold molecules and ultracold chemistry, Controlled many-body phenomena, Entanglement of molecules and dipole arrays, and Stability of molecular systems in high-frequency super-intense laser fields. The article contains 853 references.

 

Title:
Vector boson excitations near deconfined quantum critical points
Authors:
Huh, Yejin; Strack, Philipp; Sachdev, Subir
Publication:
eprint arXiv:1307.6860
Publication Date:
07/2013
Origin:
ARXIV
Keywords:
Condensed Matter - Strongly Correlated Electrons, High Energy Physics - Theory
Comment:
7 pages, 3 figures
Bibliographic Code:
2013arXiv1307.6860H

Abstract

We show that the N\'eel states of two-dimensional antiferromagnets have low energy vector boson excitations in the vicinity of deconfined quantum critical points. We compute the universal damping of these excitations arising from spin-wave emission. Detection of such a vector boson will demonstrate the existence of emergent topological gauge excitations in a quantum spin system.

 

Title:
Local spin susceptibilities of low-dimensional electron systems
Authors:
Stano, Peter; Klinovaja, Jelena; Yacoby, Amir; Loss, Daniel
Publication:
Physical Review B, vol. 88, Issue 4, id. 045441 (PhRvB Homepage)
Publication Date:
07/2013
Origin:
APS
PACS Keywords:
Static properties, Exchange correlation dielectric and magnetic response functions plasmons, Electron states and collective excitations in multilayers quantum wells mesoscopic and nanoscale systems, Magnetometers for susceptibility magnetic moment and magnetization measurements
DOI:
10.1103/PhysRevB.88.045441
Bibliographic Code:
2013PhRvB..88d5441S

Abstract

We investigate, assess, and suggest possibilities for a measurement of the local spin susceptibility of a conducting low-dimensional electron system. The basic setup of the experiment we envisage is a source-probe one. Locally induced spin density (e.g., by a magnetized atomic force microscope tip) extends in the medium according to its spin susceptibility. The induced magnetization can be detected as a dipolar magnetic field, for instance, by an ultrasensitive nitrogen-vacancy center based detector, from which the spatial structure of the spin susceptibility can be deduced. We find that one-dimensional systems, such as semiconducting nanowires or carbon nanotubes, are expected to yield a measurable signal. The signal in a two-dimensional electron gas is weaker, though materials with a high enough g-factor (such as InGaAs) seem promising for successful measurements.

 

Title:
On Exotic Sphere Fibrations, Topological Phases, and Edge States in Physical Systems
Authors:
Lin, Hai; Yau, Shing-Tung
Affiliation:
AA(Department of Physics, Harvard University, MA 02138, USA; Department of Mathematics, Harvard University, MA 02138, USA), AB(Department of Physics, Harvard University, MA 02138, USA; Department of Mathematics, Harvard University, MA 02138, USA)
Publication:
International Journal of Modern Physics B, Volume 27, Issue 19, id. 1350107 (IJMPB Homepage)
Publication Date:
07/2013
Origin:
WSPC
Keywords:
Topological insulators, magneto-electric effects, photonic crystal, exotic sphere, topological states, edge states, heterostructures, Weyl semimetals, cold atoms
Abstract Copyright:
(c) 2013: World Scientific Publishing Company
DOI:
10.1142/S0217979213501075
Bibliographic Code:
2013IJMPB..2750107L

Abstract

We suggest that exotic sphere fibrations can be mapped to band topologies in condensed matter systems. These fibrations can correspond to geometric phases of two double bands or state vector bases with second Chern numbers m+n and -n, respectively. They can be related to topological insulators, magnetoelectric effects, and photonic crystals with special edge states. We also consider time-reversal symmetry breaking perturbations of topological insulator, and heterostructures of topological insulators with normal insulators and with superconductors. We consider periodic TI/NI/TI/NI‧ heterostructures, and periodic TI/SC/TI/SC‧ heterostructures. They also give rise to models of Weyl semimetals which have thermal and electrical transports.

 

Title:
Conserved current correlators of conformal field theories in 2+1 dimensions
Authors:
Huh, Yejin; Strack, Philipp; Sachdev, Subir
Publication:
eprint arXiv:1307.6863
Publication Date:
07/2013
Origin:
ARXIV
Keywords:
Condensed Matter - Strongly Correlated Electrons, High Energy Physics - Theory
Comment:
29 pages, 10 figures, 4 tables
Bibliographic Code:
2013arXiv1307.6863H

Abstract

We compute current correlators of the CP^{N-1} field theory in 2+1 dimensions, both at the critical point and in the phase with spontaneously broken SU(N) symmetry. Universal constants are obtained to next-to-leading order in the 1/N expansion. Implications are noted for quantum critical points of antiferromagnets, and their vicinity.

 

Title:
Lacerta I and Cassiopeia III. Two Luminous and Distant Andromeda Satellite Dwarf Galaxies Found in the 3π Pan-STARRS1 Survey
Authors:
Martin, Nicolas F.; Slater, Colin T.; Schlafly, Edward F.; Morganson, Eric; Rix, Hans-Walter; Bell, Eric F.; Laevens, Benjamin P. M.; Bernard, Edouard J.; Ferguson, Annette M. N.; Finkbeiner, Douglas P.; Burgett, William S.; Chambers, Kenneth C.; Hodapp, Klaus W.; Kaiser, Nicholas; Kudritzki, Rolf-Peter; Magnier, Eugene A.; Morgan, Jeffrey S.; Price, Paul A.; Tonry, John L.; Wainscoat, Richard J.
Publication:
The Astrophysical Journal, Volume 772, Issue 1, article id. 15, 6 pp. (2013). (ApJ Homepage)
Publication Date:
07/2013
Origin:
IOP
Astronomy Keywords:
galaxies: individual: Andromeda XXXI Andromeda XXXII Cassiopeia III Lacerta I, Local Group
DOI:
10.1088/0004-637X/772/1/15
Bibliographic Code:
2013ApJ...772...15M

Abstract

We report the discovery of two new dwarf galaxies, Lacerta I/Andromeda XXXI (Lac I/And XXXI) and Cassiopeia III/Andromeda XXXII (Cas III/And XXXII), in stacked Pan-STARRS1 r P1- and i P1-band imaging data. Both are luminous systems (MV ~ -12) located at projected distances of 20.°3 and 10.°5 from M31. Lac I and Cas III are likely satellites of the Andromeda galaxy with heliocentric distances of 756^{+44}_{-28}\,kpc and 772^{+61}_{-56}\,kpc, respectively, and corresponding M31-centric distances of 275 ± 7 kpc and 144^{+6}_{-4}\,kpc. The brightest of recent Local Group member discoveries, these two new dwarf galaxies owe their late discovery to their large sizes (r_h = 4.2^{+0.4}_{-0.5} arcmin or 912^{+124}_{-93}\,pc for Lac I r_h = 6.5^{+1.2}_{-1.0} arcmin or 1456 ± 267 pc for Cas III) and consequently low surface brightness (μ0 ~ 26.0 mag arcsec-2), as well as to the lack of a systematic survey of regions at large radii from M31, close to the Galactic plane. This latter limitation is now alleviated by the 3π Pan-STARRS1 survey, which could lead to the discovery of other distant Andromeda satellite dwarf galaxies.

 

Title:
A signature-based search for delayed photons in exclusive photon plus missing transverse energy events from $p \bar{p}$ collisions with $\sqrt{s} = 1.96$ TeV
Authors:
CDF Collaboration; Aaltonen, T.; Amerio, S.; Amidei, D.; ...Guimaraes da Costa, J.;...Franklin, M.; ...; and 408 coauthors.
Publication:
eprint arXiv:1307.0474
Publication Date:
07/2013
Origin:
ARXIV
Keywords:
High Energy Physics - Experiment
Comment:
9 pages, 2 figures, to be submitted to PRD-RC
Bibliographic Code:
2013arXiv1307.0474C

Abstract

We present the first signature-based search for delayed photons using an exclusive photon plus missing transverse energy final state. Events are reconstructed in a data sample from the CDF II detector corresponding to $6.3 \text{fb}^{-1}$ of integrated luminosity from $\sqrt{s}=1.96$ TeV proton-antiproton collisions. Candidate events are selected if they contain a photon with an arrival time in the detector larger than expected from a promptly-produced photon. The mean number of events from standard model sources predicted by the data-driven background model based on the photon timing distribution is $286 \pm 24$. A total of 322 events are observed. A $p$-value of 12% is obtained, showing consistency of the data with standard model predictions.

 

Title:
Preparation of Nuclear Spin Singlet States using Spin-Lock Induced Crossing
Authors:
DeVience, Stephen J.; Walsworth, Ronald L.; Rosen, Matthew S.
Publication:
eprint arXiv:1307.0832
Publication Date:
07/2013
Origin:
ARXIV
Keywords:
Quantum Physics, Physics - Chemical Physics, Physics - Medical Physics
Comment:
5 pages, 3 figures
Bibliographic Code:
2013arXiv1307.0832D

Abstract

We introduce a broadly applicable technique to create nuclear spin singlet states in organic molecules and other many-atom systems. We employ a novel pulse sequence to produce a spin-lock induced crossing (SLIC) of the spin singlet and triplet energy levels, which enables triplet/singlet polarization transfer and singlet state preparation. We demonstrate the utility of the SLIC method by producing a long-lived nuclear spin singlet state on two strongly-coupled proton pairs in the tripeptide molecule phenylalanine-glycine-glycine dissolved in D2O, and by using SLIC to measure the J-couplings, chemical shift differences, and singlet lifetimes of the proton pairs. We show that SLIC is more efficient at creating nearly-equivalent nuclear spin singlet states than previous pulse sequence techniques, especially when triplet/singlet polarization transfer occurs on the same timescale as spin-lattice relaxation.

 

Title:
Advanced Cold Molecule Electron EDM
Authors:
ACME Collaboration; Campbell, Wesley C.; Chan, Cheong; DeMille, David; Doyle, John M.; Gabrielse, Gerald; Gurevich, Yulia V.; Hess, Paul W.; Hutzler, Nicholas R.; Kirilov, Emil; OLeary, Brendon; Petrik, Elizabeth S.; Spaun, Ben; Vutha, Amar C.
Publication:
eprint arXiv:1307.1657
Publication Date:
07/2013
Origin:
ARXIV
Keywords:
Physics - Atomic Physics
Comment:
International Conference for Atomic Physics (ICAP) 2012 proceedings paper. Accepted for publication in the European Physical Journal (EPJ). 13 pages, 5 figures, 3 tables
Bibliographic Code:
2013arXiv1307.1657A

Abstract

Measurement of a non-zero electric dipole moment (EDM) of the electron within a few orders of magnitude of the current best limit of |d_e| < 1.05 e -27 e cm would be an indication of physics beyond the Standard Model. The ACME Collaboration is searching for an electron EDM by performing a precision measurement of electron spin precession in the metastable H state of thorium monoxide (ThO) using a slow, cryogenic beam. We discuss the current status of the experiment. Based on a data set acquired from 14 hours of running time over a period of 2 days, we have achieved a 1-sigma statistical uncertainty of 1 e -28 e cm/T^(1/2), where T is the running time in days.

 

Title:
Nodal geometry of graphs on surfaces
Authors:
Lin, Yong; Lippner, Gabor; Mangoubi, Dan; Yau, Shing-Tung
Publication:
eprint arXiv:1307.3226
Publication Date:
07/2013
Origin:
ARXIV
Keywords:
Mathematics - Combinatorics, Mathematics - Spectral Theory, 39A12, 05C10, 35P0
Comment:
Discrete and Continuous Dynamical Systems Series A, Volume 28 (2010), Issue 3, Pages : 1291 - 1298; doi:10.3934/dcds.2010.28.1291
Bibliographic Code:
2013arXiv1307.3226L

Abstract

We prove two mixed versions of the Discrete Nodal Theorem of Davies et. al. [3] for bounded degree graphs, and for three-connected graphs of fixed genus $g$. Using this we can show that for a three-connected graph satisfying a certain volume-growth condition, the multiplicity of the $n$th Laplacian eigenvalue is at most $2\left[ 6(n-1) + 15(2g-2) \right]^2$. Our results hold for any Schr\"odinger operator, not just the Laplacian.

 

Title:
The Hilbert-glass transition: new universality of temperature-tuned many-body dynamical quantum criticality
Authors:
Pekker, David; Refael, Gil; Altman, Ehud; Demler, Eugene; Oganesyan, Vadim
Publication:
eprint arXiv:1307.3253
Publication Date:
07/2013
Origin:
ARXIV
Keywords:
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Disordered Systems and Neural Networks, Condensed Matter - Statistical Mechanics
Comment:
metadata updated to fix the author list, fix typos in references
Bibliographic Code:
2013arXiv1307.3253P

Abstract

In this work, we consider a new class of unconventional critical phenomena that is characterized by singularities only in dynamical quantities and has no thermodynamic signatures. A possible example is the recently proposed many-body localization transition, in which transport coefficients vanish at a critical temperature. Describing this unconventional quantum criticality has been technically challenging as understanding the finite-temperature dynamics requires the knowledge of a large number of many-body eigenstates. Here we develop a real-space renormalization group method for excited state (RSRG-X), that allow us to overcome this challenge, and establish the existence and universal properties of such temperature-tuned dynamical phase transitions. We characterize a specific example: the 1D disordered transverse field Ising model with interactions. Using RSRG-X, we find a finite-temperature transition, between two localized phases, characterized by non-analyticities of the dynamic spin correlation function and the low frequency heat conductivity.

 

Title:
Exothermic Double-Disk Dark Matter
Authors:
McCullough, Matthew; Randall, Lisa
Publication:
eprint arXiv:1307.4095
Publication Date:
07/2013
Origin:
ARXIV
Keywords:
High Energy Physics - Phenomenology, Astrophysics - Cosmology and Extragalactic Astrophysics, High Energy Physics - Experiment
Comment:
26 pages, 9 figures
Bibliographic Code:
2013arXiv1307.4095M

Abstract

If a subdominant component of dark matter (DM) interacts via long-range dark force carriers it may cool and collapse to form complex structures within the Milky Way galaxy, such as a rotating dark disk. This scenario was proposed recently and termed "Double-Disk Dark Matter" (DDDM). In this paper we consider the possibility that DDDM remains in a cosmologically long-lived excited state and can scatter exothermically on nuclei (ExoDDDM). We investigate the current status of ExoDDDM direct detection and find that ExoDDDM can readily explain the recently announced ~3 sigma excess observed at CDMS-Si, with almost all of the 90% best-fit parameter space in complete consistency with limits from other experiments, including XENON10 and XENON100. In the absence of isospin-dependent couplings, this consistency requires light DM with mass typically in the 5-15 GeV range. The hypothesis of ExoDDDM can be tested in direct detection experiments through its peaked recoil spectra, reduced annual modulation amplitude, and, in some cases, its novel time-dependence. We also discuss future direct detection prospects and additional indirect constraints from colliders and solar capture of ExoDDDM. As theoretical proof-of-principle, we combine the features of exothermic DM models and DDDM models to construct a complete model of ExoDDDM, exhibiting all the required properties.

 

Title:
In Wino Veritas? Indirect Searches Shed Light on Neutralino Dark Matter
Authors:
Fan, JiJi; Reece, Matthew
Publication:
eprint arXiv:1307.4400
Publication Date:
07/2013
Origin:
ARXIV
Keywords:
High Energy Physics - Phenomenology, Astrophysics - Cosmology and Extragalactic Astrophysics
Bibliographic Code:
2013arXiv1307.4400F

Abstract

Indirect detection constraints on gamma rays (both continuum and lines) have set strong constraints on wino dark matter. By combining results from Fermi-LAT and HESS, we show that: light nonthermal wino dark matter is strongly excluded; thermal wino dark matter is allowed only if the Milky Way dark matter distribution has a significant (>~0.4 kpc) core; and for plausible NFW and Einasto distributions the entire range of wino masses from 100 GeV up to 3 TeV can be excluded. The case of light, nonthermal wino dark matter is particularly interesting in scenarios with decaying moduli that reheat the universe to a low temperature. Typically such models have been discussed for low reheating temperatures, not far above the BBN bound of a few MeV. We show that constraints on the allowed wino relic density push such models to higher reheating temperatures and hence heavier moduli. Even for a flattened halo model consisting of an NFW profile with constant-density core inside 1 kpc and a density near the sun of 0.3 GeV/cm^3, for 150 GeV winos current data constrains the reheat temperature to be above 1.4 GeV. As a result, for models in which the wino mass is a loop factor below the gravitino mass, the data favor moduli that are more than an order of magnitude heavier than the gravitino. We discuss some of the sobering implications of this result for the status of supersymmetry. We also comment on other neutralino dark matter scenarios, in particular the case of mixed bino/higgsino dark matter. We show that in this case, direct and indirect searches are complementary to each other and could potentially cover most of the parameter space.

 

Title:
Spatial Fluctuations Of Fluid Velocities In Flow Through A Three-Dimensional Porous Medium
Authors:
Datta, Sujit S.; Chiang, Harry; Ramakrishnan, T. S.; Weitz, David A.
Publication:
eprint arXiv:1307.4539
Publication Date:
07/2013
Origin:
ARXIV
Keywords:
Condensed Matter - Soft Condensed Matter, Condensed Matter - Disordered Systems and Neural Networks, Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Fluid Dynamics, Physics - Geophysics
Comment:
In press, Physical Review Letters; Physical Review Letters 111, 064501 (2013); doi:10.1103/PhysRevLett.111.064501
Bibliographic Code:
2013arXiv1307.4539D

Abstract

We use confocal microscopy to directly visualize the spatial fluctuations in fluid flow through a three-dimensional porous medium. We find that the velocity magnitudes and the velocity components both along and transverse to the imposed flow direction are exponentially distributed, even with residual trapping of a second immiscible fluid. Moreover, we find pore-scale correlations in the flow that are determined by the geometry of the medium. Our results suggest that, despite the considerable complexity of the pore space, fluid flow through it is not completely random.

 

Title:
Driven nonlinear dynamics of two coupled exchange-only qubits
Authors:
Pal, Arijeet; Rashba, Emmanuel I.; Halperin, Bertrand I.
Publication:
eprint arXiv:1307.5075
Publication Date:
07/2013
Origin:
ARXIV
Keywords:
Condensed Matter - Mesoscale and Nanoscale Physics, Quantum Physics
Comment:
9 pages, 5 figures
Bibliographic Code:
2013arXiv1307.5075P

Abstract

Inspired by creation of a fast exchange-only qubit (Medford et al., arXiv:1304.3413), we develop a theory describing the nonlinear dynamics of two such qubits that are capacitively coupled, when one of them is driven resonantly at a frequency equal to its level splitting. We include conditions of strong driving, where the Rabi frequency is a significant fraction of the level splitting, and we consider situations where the splitting for the second qubit may be the same or different than the first. We demonstrate that coupling of qubits and entanglement between them can be detected by reading the response of the second qubit, even when the coupling between qubits is only of about 1% of their level splittings. Patterns of nonlinear dynamics of coupled qubits and their entanglement are strongly dependent on the geometry of the system and the specific mechanism of inter-qubit coupling, and entanglement deeply influences dynamics of both qubits. In particular, we describe the development of irregular dynamics in a two-qubit system, explore approaches for inhibiting it, and demonstrate existence of an optimal range of coupling strength maintaining stability during the operational time.

 

Title:
Combination of CDF and D0 W-Boson Mass Measurements
Authors:
CDF Collaboration; Aaltonen, T.; Amerio, S.; Amidei, D.;...Guimaraes da Costa, J.;...Franklin, M.; ...; and 771 coauthors.
Publication:
eprint arXiv:1307.7627
Publication Date:
07/2013
Origin:
ARXIV
Keywords:
High Energy Physics - Experiment
Comment:
Submitted to Phys. Rev. D
Bibliographic Code:
2013arXiv1307.7627C

Abstract

We summarize and combine direct measurements of the mass of the $W$ boson in $\sqrt{s} = 1.96 \text{TeV}$ proton-antiproton collision data collected by CDF and D0 experiments at the Fermilab Tevatron Collider. Earlier measurements from CDF and D0 are combined with the two latest, more precise measurements: a CDF measurement in the electron and muon channels using data corresponding to $2.2 \mathrm{fb}^{-1}$ of integrated luminosity, and a D0 measurement in the electron channel using data corresponding to $4.3 \mathrm{fb}^{-1}$ of integrated luminosity. The resulting Tevatron average for the mass of the $W$ boson is $\MW = 80\,387 \pm 16 \text{MeV}$. Including measurements obtained in electron-positron collisions at LEP yields the most precise value of $\MW = 80\,385 \pm 15 \text{MeV}$.

 

Title:
Single-File Diffusion of Flagellin in Flagellar Filaments
Authors:
Stern, Alan S.; Berg, Howard C.
Publication:
Biophysical Journal, vol. 105, issue 1, pp. 182-184
Publication Date:
07/2013
Origin:
CROSSREF
DOI:
10.1016/j.bpj.2013.05.030
Bibliographic Code:
2013BpJ...105..182S

Abstract

Not Available

 

Title:
Universal behavior of repulsive two-dimensional fermions in the vicinity of the quantum freezing point
Authors:
Babadi, Mehrtash; Skinner, Brian; Fogler, Michael M.; Demler, Eugene
Publication:
Europhysics Letters, Volume 103, Issue 1, article id. 16002 (2013).
Publication Date:
07/2013
Origin:
IOP
DOI:
10.1209/0295-5075/103/16002
Bibliographic Code:
2013EL....10316002B

Abstract

We show by a meta-analysis of the available Quantum Monte Carlo (QMC) results that two-dimensional fermions with repulsive interactions exhibit universal behavior in the strongly correlated regime, and that their freezing transition can be described using a quantum generalization of the classical Hansen-Verlet freezing criterion. We calculate the liquid-state energy and the freezing point of the 2D dipolar Fermi gas (2DDFG) using a variational method by taking ground-state wave functions of 2D electron gas (2DEG) as trial states. A comparison with the recent fixed-node diffusion Monte Carlo analysis of the 2DDFG shows that our simple variational technique captures more than 95% of the correlation energy, and predicts the freezing transition within the uncertainty bounds of QMC. Finally, we utilize the ground-state wave functions of 2DDFG as trial states and provide a variational account of the effects of finite 2D confinement width. Our results indicate significant beyond mean-field effects. We calculate the frequency of collective monopole oscillations of the quasi-2D dipolar gas as an experimental demonstration of correlation effects.

 

Title:
On Exotic Sphere Fibrations, Topological Phases, and Edge States in Physical Systems
Authors:
Lin, Hai; Yau, Shing-Tung
Publication:
International Journal of Modern Physics B, Volume 27, Issue 19, id. 1350107 (IJMPB Homepage)
Publication Date:
07/2013
Origin:
WSPC
Keywords:
Topological insulators, magneto-electric effects, photonic crystal, exotic sphere, topological states, edge states, heterostructures, Weyl semimetals, cold atoms
Abstract Copyright:
(c) 2013: World Scientific Publishing Company
DOI:
10.1142/S0217979213501075
Bibliographic Code:
2013IJMPB..2750107L

Abstract

We suggest that exotic sphere fibrations can be mapped to band topologies in condensed matter systems. These fibrations can correspond to geometric phases of two double bands or state vector bases with second Chern numbers m+n and -n, respectively. They can be related to topological insulators, magnetoelectric effects, and photonic crystals with special edge states. We also consider time-reversal symmetry breaking perturbations of topological insulator, and heterostructures of topological insulators with normal insulators and with superconductors. We consider periodic TI/NI/TI/NI‧ heterostructures, and periodic TI/SC/TI/SC‧ heterostructures. They also give rise to models of Weyl semimetals which have thermal and electrical transports.

 

Title: Measurement of the production cross section of jets in association with a Z boson in pp collisions at √{s}=7 TeV with the ATLAS detector
Authors: Aad, G.; Abajyan, T.; Abbott, B.;... Franklin, M....; Guimaraes da Costa, J.;... Huth, J.;... Morii, M.;...; and 2890 coauthors.
Publication:
Journal of High Energy Physics, Volume 2013, article id. #32
Publication Date:
07/2013
Origin:
SPRINGER
Keywords:
Hadron-Hadron Scattering
Abstract Copyright:
(c) 2013: CERN for the benefit of the ATLAS collaboration
DOI:
10.1007/JHEP07(2013)032
Bibliographic Code:
2013JHEP...07..032A

Abstract

Measurements of the production of jets of particles in association with a Z boson in pp collisions at √{s}=7 TeV are presented, using data corresponding to an integrated luminosity of 4.6 fb-1 collected by the ATLAS experiment at the Large Hadron Collider. Inclusive and differential jet cross sections in Z events, with Z decaying into electron or muon pairs, are measured for jets with transverse momentum p T > 30 GeV and rapidity | y| < 4 .4. The results are compared to next-to-leading-order perturbative QCD calculations, and to predictions from different Monte Carlo generators based on leading-order and next-to-leading-order matrix elements supplemented by parton showers. [Figure not available: see fulltext.]

 

Title:
A note on CFT correlators in three dimensions
Authors:
Giombi, Simone; Prakash, Shiroman; Yin, Xi
Publication:
Journal of High Energy Physics, Volume 2013, article id. #105
Publication Date:
07/2013
Origin:
SPRINGER
Keywords:
Field Theories in Lower Dimensions, Conformal and W Symmetry, Space-Time Symmetries
Abstract Copyright:
(c) 2013: SISSA, Trieste, Italy
DOI:
10.1007/JHEP07(2013)105
Bibliographic Code:
2013JHEP...07..105G

Abstract

In this note we present a simple method of constructing general conformally invariant three point functions of operators of various spins in three dimensions. Upon further imposing current conservation conditions, we find new parity violating structures for the three point functions involving either the stress-energy tensor, spin one currents, or higher spin currents. We find that all parity preserving structures for conformally invariant three point functions of higher spin conserved currents can be realized by free fields, whereas there is at most one parity violating structure for three point functions for each set of spins, which is not realized by free fields.

 

Title:
Pressure-Controlled Motion of Single Polymers through Solid-State Nanopores
Authors:
Lu, Bo; Hoogerheide, David P.; Zhao, Qing; Zhang, Hengbin; Tang, Zhipeng; Yu, Dapeng; Golovchenko, Jene A.
Publication:
Nano Letters, vol. 13, issue 7, pp. 3048-3052
Publication Date:
07/2013
Origin:
CROSSREF
DOI:
10.1021/nl402052v
Bibliographic Code:
2013NanoL..13.3048L

Abstract

Not Available

 

Title:
Prethermalization revealed by the relaxation dynamics of full distribution functions
Authors:
Adu Smith, D.; Gring, M.; Langen, T.; Kuhnert, M.; Rauer, B.; Geiger, R.; Kitagawa, T.; Mazets, I.; Demler, E.; Schmiedmayer, J.
Publication:
New Journal of Physics, Volume 15, Issue 7, article id. 075011 (2013).
Publication Date:
07/2013
Origin:
IOP
DOI:
10.1088/1367-2630/15/7/075011
Bibliographic Code:
2013NJPh...15g5011A

Abstract

We detail the experimental observation of the non-equilibrium many-body phenomenon prethermalization. We study the dynamics of a rapidly and coherently split one-dimensional Bose gas. An analysis based on the use of full quantum mechanical probability distributions of matter wave interference contrast reveals that the system evolves toward a quasi-steady state. This state, which can be characterized by an effective temperature, is not the final thermal equilibrium state. We compare the evolution of the system to an integrable Tomonaga–Luttinger liquid model, and show that the system dephases to a prethermalized state rather than undergoing thermalization toward a final thermal equilibrium state.

 

Title:
A low-loss photonic silica nanofiber for higher-order modes
Authors:
Ravets, S.; Hoffman, J. E.; Orozco, L. A.; Rolston, S. L.; Beadie, G.; Fatemi, F. K.
Publication:
Optics Express, vol. 21, issue 15, p. 18325
Publication Date:
07/2013
Origin:
CROSSREF
DOI:
10.1364/OE.21.018325
Bibliographic Code:
2013OExpr..2118325R

Abstract

Optical nanofibers confine light to subwavelength scales, and are of interest for the design, integration, and interconnection of nanophotonic devices. Here we demonstrate high transmission (> 97%) of the first family of excited modes through a 350 nm radius fiber, by appropriate choice of the fiber and precise control of the taper geometry. We can design the nanofibers so that these modes propagate with most of their energy outside the waist region. We also present an optical setup for selectively launching these modes with less than 1% fundamental mode contamination. Our experimental results are in good agreement with simulations of the propagation. Multimode optical nanofibers expand the photonic toolbox, and may aid in the realization of a fully integrated nanoscale device for communication science, laser science or other sensing applications.

 

Title:
Zeeman relaxation induced by spin-orbit coupling in cold antimony-helium collisions
Authors:
Connolly, Colin B.; Au, Yat Shan; Chae, Eunmi; Tscherbul, Timur V.; Buchachenko, Alexei A.; Ketterle, Wolfgang; Doyle, John M.
Publication:
Physical Review A, vol. 88, Issue 1, id. 012707 (PhRvA Homepage)
Publication Date:
07/2013
Origin:
APS
PACS Keywords:
Elastic; ultracold collisions, Interatomic potentials and forces
DOI:
10.1103/PhysRevA.88.012707
Bibliographic Code:
2013PhRvA..88a2707C

Abstract

We investigate Zeeman relaxation in cold Sb(4S3/2∘)–He collisions in a magnetic field. Ensembles of >1013 laser-ablated Sb atoms are cooled in cryogenic 4He buffer gas to 800 mK and inelastic collisions are observed to equilibrate the mJ-state distribution to the translational temperature. The ratio γ of momentum transfer to inelastic collision rates is measured to be ⩽9.1×102. We also perform quantum scattering calculations of Sb–4He collisions, based on ab initio interaction potentials, that demonstrate significant anisotropy of the ground state induced by the spin-orbit interaction. Agreement is obtained between theory and experiment with a ≈10% increase in the ab initio potential depth. This work suggests that buffer-gas-cooled pnictogen atoms lighter than Sb can be loaded into a magnetic trap.

 

Title:
Shot-noise-limited spin measurements in a pulsed molecular beam
Authors:
Kirilov, E.; Campbell, W. C.; Doyle, J. M.; Gabrielse, G.; Gurevich, Y. V.; Hess, P. W.; Hutzler, N. R.; O'Leary, B. R.; Petrik, E.; Spaun, B.; Vutha, A. C.; DeMille, D.
Publication:
Physical Review A, vol. 88, Issue 1, id. 013844 (PhRvA Homepage)
Publication Date:
07/2013
Origin:
APS
PACS Keywords:
Atomic and molecular beam sources and techniques, Charge conjugation, parity, time reversal, and other discrete symmetries
DOI:
10.1103/PhysRevA.88.013844
Bibliographic Code:
2013PhRvA..88a3844K

Abstract

Heavy diatomic molecules have been identified as good candidates for use in electron electric dipole moment (eEDM) searches. Suitable molecular species can be produced in pulsed beams, but with a total flux and/or temporal evolution that varies significantly from pulse to pulse. These variations can degrade the experimental sensitivity to changes in the spin precession phase of an electrically polarized state, which is the observable of interest for an eEDM measurement. We present two methods for measurement of the phase that provide immunity to beam temporal variations, and make it possible to reach shot-noise-limited sensitivity. Each method employs rapid projection of the spin state onto both components of an orthonormal basis. We demonstrate both methods using the eEDM-sensitive H3Δ1 state of thorium monoxide, and use one of them to measure the magnetic moment of this state with increased accuracy relative to previous determinations.

 

Title:
Preparation of nonequilibrium nuclear spin states in double quantum dots
Authors:
Gullans, M.; Krich, J. J.; Taylor, J. M.; Halperin, B. I.; Lukin, M. D.
Publication:
Physical Review B, vol. 88, Issue 3, id. 035309 (PhRvB Homepage)
Publication Date:
07/2013
Origin:
APS
PACS Keywords:
Quantum dots, Nuclear magnetic resonance and relaxation, Double nuclear magnetic resonance , dynamical nuclear polarization, Decoherence; open systems; quantum statistical methods
DOI:
10.1103/PhysRevB.88.035309
Bibliographic Code:
2013PhRvB..88c5309G

Abstract

We theoretically study the dynamic polarization of lattice nuclear spins in GaAs double quantum dots containing two electrons. In our prior work [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.104.226807 104, 226807 (2010)], we identified three regimes of long-term dynamics, including the buildup of a large difference in the Overhauser fields across the dots, the saturation of the nuclear polarization process associated with the formation of so-called dark states, and the elimination of the difference field. In particular, when the dots are different sizes, we found that the Overhauser field becomes larger in the smaller dot. Here we present a detailed theoretical analysis of these problems, including a model of the polarization dynamics and the development of a numerical method to efficiently simulate semiclassical-central-spin problems. When nuclear spin noise is included, the results agree with our prior work indicating that large difference fields and dark states are stable configurations, while the elimination of the difference field is unstable; however, in the absence of noise, we find all three steady states are achieved depending on parameters. These results are in good agreement with dynamic nuclear polarization experiments in double quantum dots.

 

Title:
Top-quark mass measurement in events with jets and missing transverse energy using the full CDF data set
Authors:
Aaltonen, T.; Amerio, S.; Amidei, D.; ...Guimaraes da Costa, J.;...Franklin, M.; ...; and 406 coauthors.
Publication:
Physical Review D, vol. 88, Issue 1, id. 011101 (PhRvD Homepage)
Publication Date:
07/2013
Origin:
APS
PACS Keywords:
Top quarks, Quark and lepton masses and mixing, Inclusive production with identified leptons, photons, or other nonhadronic particles
DOI:
10.1103/PhysRevD.88.011101
Bibliographic Code:
2013PhRvD..88a1101A

Abstract

We present a measurement of the top-quark mass using the full data set of Tevatron s=1.96TeV proton-antiproton collisions recorded by the CDF II detector, corresponding to an integrated luminosity of 8.7fb-1. The analysis uses events with one semileptonic t or t¯ decay, but without detection of the electron or muon. We select events with significant missing transverse energy and multiple jets. We veto events containing identified electrons or muons. We obtain distributions of the top-quark masses and the invariant mass of the two jets from W-boson decays from data and compare these to templates derived from signal and background samples to extract the top-quark mass and the energy scale of the calorimeter jets with in situ calibration. A likelihood fit of the templates from signal and background events to the data yields the top-quark mass, Mtop=173.93±1.64(stat)±0.87(syst)GeV/c2. This result is the most precise measurement to date of the mass of the top quark in this event topology.

 

Title: Search for nonpointing photons in the diphoton and ETmiss final state in s=7TeV proton-proton collisions using the ATLAS detector
Authors: Aad, G.; Abajyan, T.; Abbott, B.;... Franklin, M....; Guimaraes da Costa, J.;... Huth, J.;... Morii, M.;...; and 2910 coauthors.
Publication:
Physical Review D, vol. 88, Issue 1, id. 012001 (PhRvD Homepage)
Publication Date:
07/2013
Origin:
APS
PACS Keywords:
Supersymmetric models, Inclusive production with identified leptons, photons, or other nonhadronic particles, Limits on production of particles
DOI:
10.1103/PhysRevD.88.012001
Bibliographic Code:
2013PhRvD..88a2001A

Abstract

A search has been performed for photons originating in the decay of a neutral long-lived particle, exploiting the capabilities of the ATLAS electromagnetic calorimeter to make precise measurements of the flight direction of photons, as well as the calorimeter’s excellent time resolution. The search has been made in the diphoton plus missing transverse energy final state, using the full data sample of 4.8fb-1 of 7 TeV proton-proton collisions collected in 2011 with the ATLAS detector at the LHC. No excess is observed above the background expected from Standard Model processes. The results are used to set exclusion limits in the context of gauge mediated supersymmetry breaking models, with the lightest neutralino being the next-to-lightest supersymmetric particle and decaying with a lifetime in excess of 0.25 ns into a photon and a gravitino.

 

Title: Measurement of CP-violating asymmetries in B0→(ρπ)0 decays using a time-dependent Dalitz plot analysis
Authors: Lees, J. P.; Poireau, V.; Tisserand, V.;... ; Morii, M.;... and 349 coauthors..
Publication:
Physical Review D, vol. 88, Issue 1, id. 012003 (PhRvD Homepage)
Publication Date:
07/2013
Origin:
APS
PACS Keywords:
Charge conjugation, parity, time reversal, and other discrete symmetries, Quark and lepton masses and mixing
DOI:
10.1103/PhysRevD.88.012003
Bibliographic Code:
2013PhRvD..88a2003L

Abstract

We present results for a time-dependent Dalitz plot measurement of CP-violating asymmetries in the mode B0→π+π-π0. The data set is derived from the complete sample of 471×106 BB¯ meson pairs collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at the SLAC National Accelerator Laboratory operating on the Υ(4S) resonance. We extract parameters describing the time-dependent B0→ρπ decay probabilities and CP asymmetries, including C=0.016±0.059±0.036, ΔC=0.234±0.061±0.048, S=0.053±0.081±0.034, and ΔS=0.054±0.082±0.039, where the uncertainties are statistical and systematic, respectively. We perform a two-dimensional likelihood scan of the direct CP-violation asymmetry parameters for B0→ρ±π decays, finding the change in χ2 between the minimum and the origin (corresponding to no direct CP violation) to be Δχ2=6.42. We present information on the CP-violating parameter α in a likelihood scan that incorporates B±→ρπ measurements. To aid in the interpretation of our results, statistical robustness studies are performed to assess the reliability with which the true values of the physics parameters can be extracted. Significantly, these studies indicate that α cannot be reliably extracted with our current sample size, though the other physics parameters are robustly extracted.

 

Title: Search for tt¯ resonances in the lepton plus jets final state with ATLAS using 4.7fb-1 of pp collisions at s=7TeV
Authors: Aad, G.; Abajyan, T.; Abbott, B.;... Franklin, M....; Guimaraes da Costa, J.;... Huth, J.;... Morii, M.; ... and 2922 coauthors.
Publication:
Physical Review D, vol. 88, Issue 1, id. 012004 (PhRvD Homepage)
Publication Date:
07/2013
Origin:
APS
PACS Keywords:
Limits on production of particles, Extensions of electroweak gauge sector, Top quarks
DOI:
10.1103/PhysRevD.88.012004
Bibliographic Code:
2013PhRvD..88a2004A

Abstract

A search for new particles that decay into top quark pairs (tt¯) is performed with the ATLAS experiment at the LHC using an integrated luminosity of 4.7fb-1 of proton–proton (pp) collision data collected at a center-of-mass energy s=7TeV. In the tt¯→WbWb decay, the lepton plus jets final state is used, where one W boson decays leptonically and the other hadronically. The tt¯ system is reconstructed using both small-radius and large-radius jets, the latter being supplemented by a jet substructure analysis. A search for local excesses in the number of data events compared to the Standard Model expectation in the tt¯ invariant mass spectrum is performed. No evidence for a tt¯ resonance is found and 95% credibility-level limits on the production rate are determined for massive states predicted in two benchmark models. The upper limits on the cross section times branching ratio of a narrow Z' resonance range from 5.1 pb for a boson mass of 0.5 TeV to 0.03 pb for a mass of 3 TeV. A narrow leptophobic topcolor Z' resonance with a mass below 1.74 TeV is excluded. Limits are also derived for a broad color-octet resonance with Γ/m=15.3%. A Kaluza–Klein excitation of the gluon in a Randall–Sundrum model is excluded for masses below 2.07 TeV.

 

Title:
Mechanical properties of warped membranes
Authors:
Košmrlj, Andrej; Nelson, David R.
Publication:
Physical Review E, vol. 88, Issue 1, id. 012136 (PhRvE Homepage)
Publication Date:
07/2013
Origin:
APS
PACS Keywords:
Classical statistical mechanics, Mechanical properties, surface strains, Disordered solids, General theory of continuum mechanics of solids
DOI:
10.1103/PhysRevE.88.012136
Bibliographic Code:
2013PhRvE..88a2136K

Abstract

We explore how a frozen background metric affects the mechanical properties of planar membranes with a shear modulus. We focus on a special class of "warped membranes" with a preferred random height profile characterized by random Gaussian variables h(q) in Fourier space with zero mean and variance <|h(q)|2>˜q‑dh and show that in the linear response regime the mechanical properties depend dramatically on the system size L for dh≥2. Membranes with dh=4 could be produced by flash polymerization of lyotropic smectic liquid crystals. Via a self-consistent screening approximation we find that the renormalized bending rigidity increases as κR˜L(dh‑2)/2 for membranes of size L, while the Young and shear moduli decrease according to YR,μR˜L‑(dh‑2)/2 resulting in a universal Poisson ratio. Numerical results show good agreement with analytically determined exponents.

 

Title:
Gate-Defined Wires in HgTe Quantum Wells: From Majorana Fermions to Spintronics
Authors:
Reuther, Johannes; Alicea, Jason; Yacoby, Amir
Publication:
Physical Review X, vol. 3, Issue 3, id. 031011
Publication Date:
07/2013
Origin:
APS
PACS Keywords:
Quantum computation, Proximity effects, Andreev effect, SN and SNS junctions, Quantum wires, Quantum well devices
DOI:
10.1103/PhysRevX.3.031011
Bibliographic Code:
2013PhRvX...3c1011R

Abstract

We introduce a promising new platform for Majorana zero modes and various spintronics applications based on gate-defined wires in HgTe quantum wells. Because of the Dirac-like band structure for HgTe, the physics of such systems differs markedly from that of conventional quantum wires. Most strikingly, we show that the subband parameters for gate-defined HgTe wires exhibit exquisite tunability: Modest gate voltage variation allows one to modulate the Rashba spin-orbit energies from zero up to about 30 K, and the effective g factors from zero up to giant values exceeding 600. The large achievable spin-orbit coupling and g factors together allow one to access Majorana modes in this setting at exceptionally low magnetic fields while maintaining robustness against disorder. As an additional benefit, gate-defined wires (in HgTe or other settings) should greatly facilitate the fabrication of networks for refined transport experiments used to detect Majoranas, as well as the realization of non-Abelian statistics and quantum information devices.

 

Title:
Digital instability of a confined elastic meniscus
Authors:
Biggins, J. S.; Saintyves, B.; Wei, Z.; Bouchaud, E.; Mahadevan, L.
Publication:
Proceedings of the National Academy of Sciences, vol. 110, issue 31, pp. 12545-12548
Publication Date:
07/2013
Origin:
CROSSREF
DOI:
10.1073/pnas.1302269110
Bibliographic Code:
2013PNAS..11012545B

Abstract

Thin soft elastic layers serving as joints between relatively rigid bodies may function as sealants, thermal, electrical, or mechanical insulators, bearings, or adhesives. When such a joint is stressed, even though perfect adhesion is maintained, the exposed free meniscus in the thin elastic layer becomes unstable, leading to the formation of spatially periodic digits of air that invade the elastic layer, reminiscent of viscous fingering in a thin fluid layer. How- ever, the elastic instability is reversible and rate-independent, dis- appearing when the joint is unstressed. We use theory, experiments, and numerical simulations to show that the transition to the digital state is sudden (first-order), the wavelength and amplitude of the fingers are proportional to the thickness of the elastic layer, and the required separation to trigger the instability is inversely proportional to the in-plane dimension of the layer. Our study reveals the energetic origin of this instability and has implications for the strength of polymeric adhesives; it also suggests a method for patterning thin films reversibly with any arrangement of localized fingers in a digital elastic memory, which we confirm experimentally.

 

Title:
Vortex lattices and crystalline geometries
Authors:
Bao, Ning; Harrison, Sarah; Kachru, Shamit; Sachdev, Subir
Publication:
Physical Review D, vol. 88, Issue 2, id. 026002 (PhRvD Homepage)
Publication Date:
07/2013
Origin:
APS
PACS Keywords:
D branes, Gauge/string duality, Strongly correlated electron systems; heavy fermions
DOI:
10.1103/PhysRevD.88.026002
Bibliographic Code:
2013PhRvD..88b6002B

Abstract

We consider AdS2×R2 solutions supported by a magnetic field, such as those which arise in the near-horizon limit of magnetically charged AdS4 Reissner-Nordstrom black branes. In the presence of an electrically charged scalar field, such magnetic solutions can be unstable to spontaneous formation of a vortex lattice. We solve the coupled partial differential equations that govern the charged scalar, gauge field, and metric degrees of freedom to lowest nontrivial order in an expansion around the critical point and discuss the corrections to the free energy and thermodynamic functions arising from the formation of the lattice. We describe how such solutions can also be interpreted, via S-duality, as characterizing infrared crystalline phases of conformal field theories doped by a chemical potential, but in zero magnetic field; the doped conformal field theories are dual to geometries that exhibit dynamical scaling and hyperscaling violation.

 

Title:
Simplified biased random walk model for RecA-protein-mediated homology recognition offers rapid and accurate self-assembly of long linear arrays of binding sites
Authors:
Kates-Harbeck, Julian; Tilloy, Antoine; Prentiss, Mara
Publication:
Physical Review E, vol. 88, Issue 1, id. 012702 (PhRvE Homepage)
Publication Date:
07/2013
Origin:
APS
PACS Keywords:
Theory, modeling, and computer simulation, Self-assembly, DNA, Protein-polynucleotide interactions
DOI:
10.1103/PhysRevE.88.012702
Bibliographic Code:
2013PhRvE..88a2702K

Abstract

Inspired by RecA-protein-based homology recognition, we consider the pairing of two long linear arrays of binding sites. We propose a fully reversible, physically realizable biased random walk model for rapid and accurate self-assembly due to the spontaneous pairing of matching binding sites, where the statistics of the searched sample are included. In the model, there are two bound conformations, and the free energy for each conformation is a weakly nonlinear function of the number of contiguous matched bound sites.

 

Title:
Sensitive Chiral Analysis via Microwave Three-Wave Mixing
Authors:
Patterson, David; Doyle, John M.
Publication:
Physical Review Letters, vol. 111, Issue 2, id. 023008 (PhRvL Homepage)
Publication Date:
07/2013
Origin:
APS
PACS Keywords:
Optical activity and dichroism, Submillimeter wave, microwave and radiowave spectrometers; magnetic resonance spectrometers, auxiliary equipment, and techniques, Optical activity, Analytical methods involving rotational spectroscopy
DOI:
10.1103/PhysRevLett.111.023008
Bibliographic Code:
2013PhRvL.111b3008P

Abstract

We demonstrate chirality-induced three-wave mixing in the microwave regime, using rotational transitions in cold gas-phase samples of 1,2-propanediol and 1,3-butanediol. We show that bulk three-wave mixing, which can only be realized in a chiral environment, provides a sensitive, species-selective probe of enantiomeric excess and is applicable to a broad class of molecules. The doubly resonant condition provides simultaneous identification of species and of handedness, which should allow sensitive chiral analysis even within a complex mixture.

 

Title:
Bond Order in Two-Dimensional Metals with Antiferromagnetic Exchange Interactions
Authors:
Sachdev, Subir; La Placa, Rolando
Publication:
Physical Review Letters, vol. 111, Issue 2, id. 027202 (PhRvL Homepage)
Publication Date:
07/2013
Origin:
APS
PACS Keywords:
Band and itinerant models, Lattice fermion models, Non-Fermi-liquid ground states, electron phase diagrams and phase transitions in model systems
DOI:
10.1103/PhysRevLett.111.027202
Bibliographic Code:
2013PhRvL.111b7202S

Abstract

We present an unrestricted Hartree-Fock computation of charge-ordering instabilities of two-dimensional metals with antiferromagnetic exchange interactions, allowing for arbitrary ordering wave vectors and internal wave functions of the particle-hole pair condensate. We find that the ordering has a dominant d symmetry of rotations about lattice points for a range of ordering wave vectors, including those observed in recent experiments at low temperatures on YBa2Cu3Oy. This d symmetry implies the charge ordering is primarily on the bonds of the Cu lattice, and we propose incommensurate bond order parameters for the underdoped cuprates. The field theory for the onset of Néel order in a metal has an emergent pseudospin symmetry which “rotates” d-wave Cooper pairs to particle-hole pairs [M. A. Metlitski and S. Sachdev, Phys. Rev. B 82, 075128 (2010)PRBMDO1098-012110.1103/PhysRevB.82.075128]; our results show that this symmetry has consequences even when the spin correlations are short ranged and incommensurate.

 

Title:
Search for Pair Production of Strongly Interacting Particles Decaying to Pairs of Jets in pp¯ Collisions at s=1.96TeV
Authors:
Aaltonen, T.; Albin, E.; Amerio, S.;... Guimaraes da Costa, J.;...Franklin, M.; ...; and 407 coauthors.
Publication:
Physical Review Letters, vol. 111, Issue 3, id. 031802 (PhRvL Homepage)
Publication Date:
07/2013
Origin:
APS
PACS Keywords:
Limits on production of particles, Models beyond the standard model, Other particles
DOI:
10.1103/PhysRevLett.111.031802
Bibliographic Code:
2013PhRvL.111c1802A

Abstract

We present a search for the pair production of a narrow nonstandard-model strongly interacting particle that decays to a pair of quarks or gluons, leading to a final state with four hadronic jets. We consider both nonresonant production via an intermediate gluon as well as resonant production via a distinct nonstandard-model intermediate strongly interacting particle. We use data collected by the CDF experiment in proton-antiproton collisions at s=1.96TeV corresponding to an integrated luminosity of 6.6fb-1. We find the data to be consistent with nonresonant production. We report limits on σ(pp¯→jjjj) as a function of the masses of the hypothetical intermediate particles. Upper limits on the production cross sections for nonstandard-model particles in several resonant and nonresonant processes are also derived.

 

Title:
Measurement of the Cross Section for Direct-Photon Production in Association with a Heavy Quark in pp¯ Collisions at s=1.96TeV
Authors:
Aaltonen, T.; Amerio, S.; Amidei, D.; ...Guimaraes da Costa, J.;...Franklin, M.; ...; and 406 coauthors.
Publication:
Physical Review Letters, vol. 111, Issue 4, id. 042003 (PhRvL Homepage)
Publication Date:
07/2013
Origin:
APS
PACS Keywords:
Experimental tests, Inclusive production with identified leptons, photons, or other nonhadronic particles, Production
DOI:
10.1103/PhysRevLett.111.042003
Bibliographic Code:
2013PhRvL.111d2003A

Abstract

We report on a measurement of the cross section for direct-photon production in association with a heavy quark using the full data set of s=1.96TeV proton-antiproton collisions corresponding to 9.1fb-1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron. The measurements are performed as a function of the photon transverse momentum, covering a photon transverse momentum between 30 and 300 GeV, photon rapidities |yγ|<1.0, a heavy-quark-jet transverse momentum pTjet>20GeV, and jet rapidities |yjet|<1.5. The results are compared with several theoretical predictions.

 


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