scholarly journals Cross-section measurements of final states with photons and jets with the ATLAS experiment

2018 ◽  
Vol 172 ◽  
pp. 02002
Author(s):  
Miguel Villaplana Pérez
Keyword(s):  
Cross Section ◽  
Transverse Energy ◽  
Atlas Collaboration ◽  
Final States ◽  
Coupling Constant ◽  
Centre Of Mass ◽  
Art Theory ◽  
Atlas Experiment ◽  
Renormalization Group Equations ◽  
8 Tev

The ATLAS Collaboration has performed precise measurements of the cross-section of final states with photons and/or jets at centre-of-mass energies of 8 and 13 TeV. The results are compared with state-of-the-art theory predictions and with predictions of several Monte Carlo generators. We also present new measurements of transverse energy-energy correlations and their associated asymmetries in multi-jet events at 8 TeV. Both measurements are used to extract the strong coupling constant and test the renormalization group equations.

scholarly journals Probing QCD with Photons and Jets at the ATLAS detector

2018 ◽  
Vol 182 ◽  
pp. 02025
Author(s):  
Giuseppe Callea
Keyword(s):  
Cross Sections ◽  
Transverse Energy ◽  
Renormalization Group Equation ◽  
Atlas Collaboration ◽  
Group Equation ◽  
Final States ◽  
Leading Order ◽  
Coupling Constant ◽  
Centre Of Mass ◽  
8 Tev

This contribution gives an overview of the recent measurements of the differential cross sections for final states involving photons and/or jets at the centre-of-mass energies of 8 and 13 TeV, published by the ATLAS Collaboration. The results are compared with several next-to-leading order calculations and with the latest predictions of various Monte Carlo generators. New measurements of transverse energy-energy correlations and their associated asymmetries in multi-jet events at 8 TeV are also presented. Both measurements are used to extract the strong coupling constant and test the renormalization group equation.

scholarly journals $$ t\overline{t}t\overline{t} $$ signatures through the lens of color-octet scalars

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Linda M. Carpenter ◽  
Taylor Murphy ◽  
Matthew J. Smylie
Keyword(s):  
Cross Section ◽  
Transverse Energy ◽  
Production Cross ◽  
Top Quarks ◽  
Atlas Collaboration ◽  
Missing Transverse Energy ◽  
Color Octet ◽  
Section Measurement ◽  
Discovery Potential ◽  
New Phenomena

Abstract We reinterpret two recent LHC searches for events containing four top quarks $$ \left(t\overline{t}t\overline{t}\right) $$ t t ¯ t t ¯ in the context of supersymmetric models with Dirac gauginos and color-octet scalars (sgluons). We explore whether sgluon contributions to the four-top production cross section $$ \sigma \left( pp\to t\overline{t}t\overline{t}\right) $$ σ pp → t t ¯ t t ¯ can accommodate an excess of four-top events recently reported by the ATLAS collaboration. We also study constraints on these models from an ATLAS search for new phenomena with high jet multiplicity and significant missing transverse energy $$ \left({E}_{\mathrm{T}}^{\mathrm{miss}}\right) $$ E T miss sensitive to signals with four top quarks. We find that these two analyses provide complementary constraints, with the jets + $$ {E}_{\mathrm{T}}^{\mathrm{miss}} $$ E T miss search exceeding the four-top cross section measurement in sensitivity for sgluons heavier than about 800 GeV. We ultimately find that either a scalar or a pseudoscalar sgluon can currently fit the ATLAS excess in a range of reasonable benchmark scenarios, though a pseudoscalar in minimal Dirac gaugino models is ruled out. We finally offer sensitivity projections for these analyses at the HL-LHC, mapping the 5σ discovery potential in sgluon parameter space and computing exclusion limits at 95% CL in scenarios where no excess is found.

scholarly journals MULTIJET PRODUCTION IN NEUTRAL CURRENT DEEP INELASTIC SCATTERING AT HERA AND DETERMINATION OF αs

2005 ◽  
Vol 20 (08n09) ◽  
pp. 2002-2005
Author(s):  
LIANG LI
Keyword(s):  
Inelastic Scattering ◽  
Deep Inelastic Scattering ◽  
Cross Sections ◽  
Transverse Energy ◽  
Neutral Current ◽  
Coupling Constant ◽  
Centre Of Mass ◽  
Multijet Production ◽  
Energy Formula

Multijet production rates in neutral current deep inelastic scattering (DIS) have been measured in the range of exchanged boson virtualities 10<Q2<5000 GeV2. The data were taken at the ep collider HERA with centre-of-mass energy [Formula: see text] using the ZEUS detector and correspond to an integrated luminosity of 82.2 pb-1. Jets were identified in the Breit frame using the kTcluster algorithm in the longitudinally invariant inclusive mode. Measurements of differential multijet cross sections are presented as functions of jet transverse energy [Formula: see text], pseudorapidity [Formula: see text] and Q2with [Formula: see text] and [Formula: see text]. Next-to-leading-order QCD calculations describe the data well. The value of the strong coupling constant αs(MZ), determined from the ratio of the trijet to dijet cross sections, is [Formula: see text].

scholarly journals ATLAS Open Data – Development of a simple-but-real HEP data analysis framework

2020 ◽  
Vol 245 ◽  
pp. 08023
Author(s):  
Farid Ould-Saada
Keyword(s):  
Programming Languages ◽  
Hadron Collider ◽  
Open Data ◽  
Simulated Data ◽  
Atlas Collaboration ◽  
Real Analysis ◽  
Centre Of Mass ◽  
Analysis Framework ◽  
Regular Classrooms ◽  
8 Tev

The ATLAS Collaboration at the Large Hadron Collider is releasing a new set of recorded and simulated data samples at a centre-of-mass energy of 13 TeV collected in pp collisions at the LHC. This new dataset was designed after an in-depth review of the usage of the previous release of samples at 8 TeV. That review showed that capacity-building is one of the most important and abundant uses of public ATLAS samples. To fulfil the requirements of the community and at the same time attract new users and use cases, we developed real analysis software based on ROOT in two of the most popular programming languages: C++ and Python. These so-called analysis frameworks are complex enough to reproduce with reasonable accuracy the results -figures and final yields- of published ATLAS Collaboration physics papers, but still light enough to be run on commodity hardware. With the computers that university students and regular classrooms typically have, students can explore LHC data with similar techniques to those used by current ATLAS analysers. We present the development path and the final result of these analysis frameworks, their products and how they are distributed to final users inside and outside the ATLAS community.

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