98 research outputs found
New results from glueball superpotentials and matrix models: the Leigh-Strassler deformation
No full textUsing the result of a matrix model computation of the exact glueball superpotential, we investigate the relevant mass perturbations of the Leigh-Strassler marginal ``q'' deformation of N=4 supersymmetric gauge theory. We recall a conjecture for the elliptic superpotential that describes the theory compactified on a circle and identify this superpotential as one of the Hamiltonians of the elliptic Ruijsenaars-Schneider integrable system. In the limit that the Leigh-Strassler deformation is turned off, the integrable system reduces to the elliptic Calogero-Moser system which describes the N=1^* theory. Based on these results, we identify the Coulomb branch of the partially mass-deformed Leigh-Strassler theory as the spectral curve of the Ruijsenaars-Schneider system. We also show how the Leigh-Strassler deformation may be obtained by suitably modifying Witten's M theory brane construction of N=
Geometric transition versus cascading solution
No full textWe study Vafa's geometric transition and Klebanov-Strassler solution from various points of view in M-theory. In terms of brane configurations, we show the detailed equivalences between the two models. In some limits, both models have an alternative realization as fourfolds in M-theory with appropriate G-fluxes turned on. We discuss some aspects of the fourfolds including how to see the transition and a possible extension to the non-supersymmetric case.open1127sciescopu
Triggers for displaced decays of long-lived neutral particles in the ATLAS detector
No full textA set of three dedicated triggers designed to detect long-lived neutral particles decaying throughout the ATLAS detector to a pair of hadronic jets is described. The efficiencies of the triggers for selecting displaced decays as a function of the decay position are presented for simulated events. The effect of pile-up interactions on the trigger efficiencies and the dependence of the trigger rate on instantaneous luminosity during the 2012 data-taking period at the LHC are discussed
Standalone vertex finding in the ATLAS muon spectrometer
No full textContains fulltext :
127839pub.pdf (Publisher’s version ) (Open Access)
Contains fulltext :
127839.pdf (Author’s version preprint ) (Open Access
A search for jet extinction in the inclusive jet Pt spectrum in proton-proton collisions with center-of-mass energy of 7 TeV at the CMS experiment
No full textThe unification of the Standard Model of physics with the theory of general relativity is one of the most salient problems facing theoretical physicists today. A search is presented for strongly-coupled string theory, a possible resolution to this problem. At an accelerator experiment, evidence for this theory could manifest as a shutting off of all Standard Model processes. This phenomenon is referred to as extinction, beyond some energy threshold related to an extinction scale M. The search presented here utilizes 5.0 inverse femtobarns of data taken in proton-proton collisions at sqrt(s) = 7 TeV. These data were taken by the Compact Muon Solenoid (CMS) experiment, situated at the Large Hadron Collider (LHC). The Standard Model predicts the formation of collinear streams of particles known as jets, with one of the highest production cross-sections of any process expected in proton-proton collisions. The transverse momentum distribution of all jets in data is constructed, and compared to that expected by the Standard Model, as well as that expected by extinction physics for various values of M. The standard model and extinction hypotheses are expressed in terms of an explicit calculation of perturbative quantum chromodynamics (pQCD) at next-to-leading order. No significant evidence of an extinction signature is observed, and an upper limit of 3.2 TeV is set on the scale M at 95% C.L.Ph. D.Includes bibliographical referencesby Keith J. Ros
Thermal transitions of metastable M-branes
No full textWe use blackfold methods to analyse the properties of putative supergravity solutions in M-theory that describe the backreaction of polarised anti-M2 branes (namely, M5 branes wrapping three-cycles with negative M2-brane charge) in the Cvetic-Gibbons-Lu-Pope background of eleven-dimensional supergravity. At zero temperature we recover the metastable state of Klebanov and Pufu directly in supergravity. At finite temperature we uncover a previously unknown pattern of mergers between fat or thin M5-brane states with the thermalised version of the metastable state. At sufficiently small values of the anti-brane charge a single fat-metastable merger follows the same pattern recently discovered for polarised anti-D3-branes in the Klebanov-Strassler solution in type IIB supergravity. We provide quantitative evidence that this merger is driven by properties of the horizon geometry. For larger values of the anti-brane charge the wrapped M5-brane solutions exhibit different patterns of finite-temperature transitions that have no known counterpart in the anti-D3 system in Klebanov-Strassler.</p
New Nonexistence Results on Circulant Weighing Matrices
No full textA circulant weighing matrix W = (wi,j ) ∈ CW(n, k) is a square matrix of order n and entries wi,j in {-1, 0, +1} such that WWT = kIn. In his thesis [7], Strassler gave tables of known results on such matrices with n ≤ 200 and k ≤ 100. In the latest version of Strassler’s tables given by Tan [8], there are 34 open cases remaining. In this paper we resolve six of these cases, showing that there are no weight 81 CW matrices for n = 110, 130, 143 or 154, and also no CW(116, 49) or CW(143, 36)
Search for WH production with a light Higgs boson decaying to prompt electron-jets in proton–proton collisions at √s=7 TeV with the ATLAS detector
No full textContains fulltext :
111226.pdf (Author’s version preprint ) (Open Access
Vector meson production at low x from gauge/gravity duality
No full textWe use gauge/gravity duality to study vector meson (J/?, ? 0 , ?, ?) production in electron-proton scattering, in the limit of high center of mass energy at fixed momentum transfer, corresponding to the limit of low Bjorken x, where the process is dominated by pomeron exchange. Our approach considers the pomeron at strong coupling, described by the graviton Regge trajectory in AdS space with a hard-wall to mimic confinement effects. Both the proton and vector mesons are described by simple holographic wave functions in AdS. This model agrees with HERA H1 data with a ? 2 per degree of freedom below one on total cross-sections, and below two on differential cross-sections, confirming the success of previous studies that model low x DIS and DVCS using gauge/gravity duality
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