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313 papers found.
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Glueball dark matter in non-standard cosmologies

Hidden sector glueball dark matter is well motivated by string theory, compactifications of which often have extra gauge groups uncoupled to the visible sector. We study the dynamics of glueballs in theories with a period of late time primordial matter domination followed by a low final reheating temperature due to a gravitationally coupled modulus. Compared to scenarios with a ...

Neutrino mass from M theory SO(10)

We study the origin of neutrino mass from SO(10) arising from M Theory compactified on a G 2-manifold. This is linked to the problem of the breaking of the extra U(1) gauge group, in the SU(5) × U(1) subgroup of SO(10), which we show can achieved via a (generalised) Kolda-Martin mechanism. The resulting neutrino masses arise from a combination of the seesaw mechanism and induced ...

Prospects for observing charginos and neutralinos at a 100 TeV proton-proton collider

We investigate the prospects for discovering charginos and neutralinos at a future pp collider with \( \sqrt{s} \) = 100 TeV. We focus on models where squarks and sleptons are decoupled — as motivated by the LHC data. Our initial study is based on models where Higgsinos form the main component of the LSP and W -inos compose the heavier chargino states (M 2 > μ), though it is ...

Search for direct top squark pair production in events with a Higgs or Z boson, and missing transverse momentum in \( \sqrt{s}=13 \) TeV pp collisions with the ATLAS detector

A search for direct top squark pair production resulting in events with either a same-flavour opposite-sign dilepton pair with invariant mass compatible with a Z boson or a pair of jets compatible with a Standard Model (SM) Higgs boson (h) is presented. Requirements on the missing transverse momentum, together with additional selections on leptons, jets, jets identified as ...

Fiducial, total and differential cross-section measurements of t-channel single top-quark production in pp collisions at 8 TeV using data collected by the ATLAS detector

Detailed measurements of t-channel single top-quark production are presented. They use 20.2 fb\(^{-1}\) of data collected by the ATLAS experiment in proton–proton collisions at a centre-of-mass energy of 8 TeV at the LHC. Total, fiducial and differential cross-sections are measured for both top-quark and top-antiquark production. The fiducial cross-section is measured with a ...

R-parity conservation from a top down perspective

Motivated by results from the LHC and dark matter searches, we study the possibility of phenomenologically viable R-parity violation in SU(5) GUT models from a top-down point of view. We show that in contrast to the more model dependent bounds on the proton lifetime, the limits on neutrino masses provide a robust, stringent and complementary constraint on all SU(5) GUT-based ...

Microwave-assisted chemical reduction routes for direct synthesis of Fe–Pt nanoparticles in ordered face centered tetragonal L10 phase

S. Acharya 0 K. Singh 0 0 S. Acharya (&) K. Singh Department of Physics, Rashtrasant Tukdoji Maharaj Nagpur University , Nagpur 440033, Maharashtra, India In the present work, microwave-assisted

Jet reconstruction and performance using particle flow with the ATLAS Detector

This paper describes the implementation and performance of a particle flow algorithm applied to 20.2 fb\(^{-1}\) of ATLAS data from 8 TeV proton–proton collisions in Run 1 of the LHC. The algorithm removes calorimeter energy deposits due to charged hadrons from consideration during jet reconstruction, instead using measurements of their momenta from the inner tracker. This improves ...

Measurements of electroweak \(Wjj \) production and constraints on anomalous gauge couplings with the ATLAS detector

Measurements of the electroweak production of a W boson in association with two jets at high dijet invariant mass are performed using \(\sqrt{s} =\) 7 and 8 \(\text {TeV}\) proton–proton collision data produced by the Large Hadron Collider, corresponding respectively to 4.7 and 20.2 fb\(^{-1}\) of integrated luminosity collected by the ATLAS detector. The measurements are sensitive ...

Topological cell clustering in the ATLAS calorimeters and its performance in LHC Run 1

The reconstruction of the signal from hadrons and jets emerging from the proton–proton collisions at the Large Hadron Collider (LHC) and entering the ATLAS calorimeters is based on a three-dimensional topological clustering of individual calorimeter cell signals. The cluster formation follows cell signal-significance patterns generated by electromagnetic and hadronic showers. In ...

Studies of Zγ production in association with a high-mass dijet system in pp collisions at \( \sqrt{s}=8 \) TeV with the ATLAS detector

The production of a Z boson and a photon in association with a high-mass dijet system is studied using 20.2 fb−1 of proton-proton collision data at a centre-of-mass energy of \( \sqrt{s}=8 \) TeV recorded with the ATLAS detector in 2012 at the Large Hadron Collider. Final states with a photon and a Z boson decaying into a pair of either electrons, muons, or neutrinos are analysed. ...

Kahler independence of the G 2-MSSM

The G 2-MSSM is a model of particle physics coupled to moduli fields with interesting phenomenology both for colliders and astrophysical experiments. In this paper we consider a more general model—whose moduli Kahler potential is a completely arbitrary G 2-holonomy Kahler potential and whose matter Kahler potential is also more general. We prove that the vacuum structure and ...

Measurement of multi-particle azimuthal correlations in pp, p + Pb and low-multiplicity Pb + Pb collisions with the ATLAS detector

Multi-particle cumulants and corresponding Fourier harmonics are measured for azimuthal angle distributions of charged particles in \(pp\) collisions at \(\sqrt{s}\) = 5.02 and 13 TeV and in \(p\) + Pb collisions at \(\sqrt{s_{_\text {NN}}}\) = 5.02 TeV, and compared to the results obtained for low-multiplicity \(\mathrm{Pb}~+~\mathrm{Pb}\) collisions at \(\sqrt{s_{_\text {NN}}}\) ...

Energy dependence of forward-rapidity \(\mathrm {J}/\psi \) and \(\psi \mathrm {(2S)}\) production in pp collisions at the LHC

We present results on transverse momentum (\(p_{\mathrm {\textsc {t}}}\)) and rapidity (\(y\)) differential production cross sections, mean transverse momentum and mean transverse momentum square of inclusive \(\mathrm {J}/\psi \) and \(\psi \mathrm {(2S)}\) at forward rapidity (\(2.515\) GeV/c the non-prompt contribution reaches up to 50% of the total charmonium yield.

Search for dark matter at \(\sqrt{s}=13~\mathrm{TeV}\) in final states containing an energetic photon and large missing transverse momentum with the ATLAS detector

Results of a search for physics beyond the Standard Model in events containing an energetic photon and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. As the number of events observed in data, corresponding to an integrated luminosity of 36.1 fb\(^{-1}\) of proton–proton collisions at a centre-of-mass energy of ...

Precision measurement and interpretation of inclusive \(W^+\) , \(W^-\) and \(Z/\gamma ^*\) production cross sections with the ATLAS detector

High-precision measurements by the ATLAS Collaboration are presented of inclusive \(W^+ \rightarrow \ell ^+\nu \), \(W^- \rightarrow \ell ^-\bar{\nu }\) and \(Z/\gamma ^* \rightarrow \ell \ell \) (\(\ell =e,\mu \)) Drell–Yan production cross sections at the LHC. The data were collected in proton–proton collisions at \(\sqrt{s} = 7\,\text {TeV}\) with an integrated luminosity of ...

Measurements of the production cross section of a \(Z\) boson in association with jets in pp collisions at \(\sqrt{s} = 13\) TeV with the ATLAS detector

Measurements of the production cross section of a \(Z\) boson in association with jets in proton–proton collisions at \(\sqrt{s} = 13\) TeV are presented, using data corresponding to an integrated luminosity of 3.16 fb\(^{-1}\) collected by the ATLAS experiment at the CERN Large Hadron Collider in 2015. Inclusive and differential cross sections are measured for events containing a ...

Measurement of jet fragmentation in Pb+Pb and pp collisions at \(\sqrt{{s_\mathrm{NN}}} = 2.76\) TeV with the ATLAS detector at the LHC

The distributions of transverse momentum and longitudinal momentum fraction of charged particles in jets are measured in Pb+Pb and pp collisions with the ATLAS detector at the LHC. The distributions are measured as a function of jet transverse momentum and rapidity. The analysis utilises an integrated luminosity of 0.14 nb\(^{-1}\) of Pb+Pb data and 4.0 pb\(^{-1}\) of pp data ...

Measurements of top-quark pair differential cross-sections in the \(e\mu \) channel in pp collisions at \(\sqrt{s} = 13\) TeV using the ATLAS detector

This article presents measurements of \(t\bar{t}\) differential cross-sections in a fiducial phase-space region, using an integrated luminosity of 3.2 fb\(^{-1}\) of proton–proton data at a centre-of-mass energy of \(\sqrt{s} = 13\) TeV recorded by the ATLAS experiment at the LHC in 2015. Differential cross-sections are measured as a function of the transverse momentum and absolute ...

Performance of the ATLAS trigger system in 2015

During 2015 the ATLAS experiment recorded \(3.8\,{\mathrm{fb}}^{-1}\) of proton–proton collision data at a centre-of-mass energy of \(13\,{\mathrm{TeV}}\). The ATLAS trigger system is a crucial component of the experiment, responsible for selecting events of interest at a recording rate of approximately 1 kHz from up to 40 MHz of collisions. This paper presents a short overview of ...