scholarly journals Observation and measurements of vector-boson scattering with the ATLAS detector

2020 ◽  
Vol 35 (34n35) ◽  
pp. 2044002
Author(s):  
Ondřej Penc
Keyword(s):  
Cross Sections ◽  
Vector Boson ◽  
Center Of Mass ◽  
New Physics ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Number Of Generators ◽  
Text Production ◽  
Vector Boson Scattering ◽  
Electroweak Boson

The scattering of electroweak bosons tests the gauge structure of the Standard Model and is sensitive to anomalous quartic gauge couplings. In this paper, we present recent results on vector-boson scattering from the ATLAS experiment using proton–proton collisions with a center-of-mass energy of 13 TeV at the LHC. This includes the observation of [Formula: see text], [Formula: see text], and same-sign [Formula: see text] production via vector-boson scattering along with a measurement of [Formula: see text] production ([Formula: see text] denotes [Formula: see text] or [Formula: see text] boson) in semileptonic final states. The results can be used to constrain new physics that manifests as anomalous electroweak-boson self-interactions. Finally, predicted cross-sections for the electroweak scattering of two same-sign [Formula: see text] bosons in association with two jets are compared for a number of generators.

scholarly journals Search for physics beyond the standard model in events with jets and two same-sign or at least three charged leptons in proton-proton collisions at $$\sqrt{s}=13\,{\text {TeV}} $$

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  
Keyword(s):  
Standard Model ◽  
Cross Sections ◽  
Center Of Mass ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
Charged Leptons ◽  
Proton Proton Collisions

Abstract A data sample of events from proton-proton collisions with at least two jets, and two isolated same-sign or three or more charged leptons, is studied in a search for signatures of new physics phenomena. The data correspond to an integrated luminosity of $$137{\,{\text {fb}}^{-1}} $$137fb-1 at a center-of-mass energy of $$13\,{\text {TeV}} $$13TeV, collected in 2016–2018 by the CMS experiment at the LHC. The search is performed using a total of 168 signal regions defined using several kinematic variables. The properties of the events are found to be consistent with the expectations from standard model processes. Exclusion limits at 95% confidence level are set on cross sections for the pair production of gluinos or squarks for various decay scenarios in the context of supersymmetric models conserving or violating R parity. The observed lower mass limits are as large as $$2.1\,{\text {TeV}} $$2.1TeV for gluinos and $$0.9\,{\text {TeV}} $$0.9TeV for top and bottom squarks. To facilitate reinterpretations, model-independent limits are provided in a set of simplified signal regions.

scholarly journals tt̄H Coupling Measurement with the ATLAS Detector at the LHC

2018 ◽  
Vol 182 ◽  
pp. 02052
Author(s):  
Asma Hadef
Keyword(s):  
Higgs Boson ◽  
Cross Sections ◽  
Top Quark ◽  
High Energy Physics ◽  
Center Of Mass ◽  
High Energy ◽  
New Physics ◽  
Decay Modes ◽  
Center Of Mass Energy ◽  
Higgs Decay

The Higgs boson was discovered on the 4th of July 2012 with a mass around 125 GeV by ATLAS and CMS experiments at LHC. Determining the Higgs properties (production and decay modes, couplings,...) is an important part of the high-energy physics programme in this decade. A search for the Higgs boson production in association with a top quark pair (tt̄H) at ATLAS [1] is summarized in this paper at an unexplored center-of-mass energy of 13 TeV, which could allow a first direct measurement of the top quark Yukawa coupling and could reveal new physics. The tt̄H analysis in ATLAS is divided into 3 channels according to the Higgs decay modes: H → Hadrons, H → Leptons and H → Photons. The best-fit value of the ratio of observed and Standard Model cross sections of tt̄H production process, using 2015-2016 data and combining all tt̄H final states, is 1:8±0:7, corresponds to 2:8σ (1:8σ) observed (expected) significance.

Implementation of the ATLAS-SUSY-2018-32 analysis (sleptons and eletroweakinos with two leptons and missing transverse energy; 139 fb−1)

2020 ◽  
pp. 2141005
Author(s):  
Jack Y. Araz ◽  
Benjamin Fuks
Keyword(s):  
Pair Production ◽  
Transverse Energy ◽  
Center Of Mass ◽  
New Physics ◽  
Missing Transverse Energy ◽  
Missing Energy ◽  
Final State ◽  
Proton Proton ◽  
Weak Boson ◽  
Center Of Mass Energy

We present the implementation in MadAnalysis 5 of the ATLAS-SUSY-2018-32 search for new physics and document the validation of this re-implementation. This analysis targets, with 139 fb[Formula: see text] of proton–proton collisions at a center-of-mass energy of 13 TeV recorded by the ATLAS detector, the electroweak pair production of supersymmetric charginos and sleptons when they further decay into a final state comprising a pair of leptons and missing energy. The validation of our work is based on three [Formula: see text]-parity conserving supersymmetric benchmark setups that feature, respectively, chargino pair-production followed by decays into leptons via an intermediate weak boson, chargino pair-production followed by chargino cascade decays into leptons through a slepton mediator, and slepton pair-production followed by slepton direct decays into leptons.

scholarly journals JET RESULTS AND JET RECONSTRUCTION TECHNIQUES IN p+p AND THEIR PROSPECTS IN HEAVY-ION COLLISIONS IN ATLAS

2011 ◽  
Vol 20 (07) ◽  
pp. 1545-1550
Author(s):  
◽  
MARTIN SPOUSTA
Keyword(s):  
Cross Sections ◽  
Heavy Ion Collisions ◽  
Center Of Mass ◽  
Heavy Ion ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Ion Collisions ◽  
Expected Performance ◽  
Jet Shapes ◽  
Jet Cross Sections

We present the measurement of jet production performed with the ATLAS detector in proton-proton collisions at center-of-mass energy of 7 TeV, using an integrated luminosity of 17 nb−1. We show the inclusive jet cross sections and jet shapes. The expected performance and strategy for the jet reconstruction in heavy ion collisions is also discussed.

scholarly journals Future Circular Colliders

2019 ◽  
Vol 69 (1) ◽  
pp. 389-415 ◽  
Author(s):  
M. Benedikt ◽  
A. Blondel ◽  
P. Janot ◽  
M. Klein ◽  
M. Mangano ◽  
...  
Keyword(s):  
Particle Physics ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Heavy Ion ◽  
New Physics ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
Physics Program ◽  
Electron Positron

After 10 years of physics at the Large Hadron Collider (LHC), the particle physics landscape has greatly evolved. Today, a staged Future Circular Collider (FCC), consisting of a luminosity-frontier highest-energy electron–positron collider (FCC-ee) followed by an energy-frontier hadron collider (FCC-hh), promises the most far-reaching physics program for the post-LHC era. FCC-ee will be a precision instrument used to study the Z, W, Higgs, and top particles, and will offer unprecedented sensitivity to signs of new physics. Most of the FCC-ee infrastructure could be reused for FCC-hh, which will provide proton–proton collisions at a center-of-mass energy of 100 TeV and could directly produce new particles with masses of up to several tens of TeV. This collider will also measure the Higgs self-coupling and explore the dynamics of electroweak symmetry breaking. Thermal dark matter candidates will be either discovered or conclusively ruled out by FCC-hh. Heavy-ion and electron–proton collisions (FCC-eh) will further contribute to the breadth of the overall FCC program. The integrated FCC infrastructure will serve the particle physics community through the end of the twenty-first century. This review combines key contents from the first three volumes of the FCC Conceptual Design Report.

Search for physics beyond the Standard Model using jet observables

2015 ◽  
Vol 30 (31) ◽  
pp. 1546009 ◽  
Author(s):  
Konstantinos Kousouris
Keyword(s):  
Standard Model ◽  
Center Of Mass ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Final States ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
The Standard Model ◽  
8 Tev ◽  
Jet Observables

Jet observables have been exploited extensively during the LHC Run 1 to search for physics beyond the Standard Model. In this article, the most recent results from the ATLAS and CMS collaborations are summarized. Data from proton–proton collisions at 7 and 8 TeV center-of-mass energy have been analyzed to study monojet, dijet, and multijet final states, searching for a variety of new physics signals that include colored resonances, contact interactions, extra dimensions, and supersymmetric particles. The exhaustive searches with jets in Run 1 did not reveal any signal, and the results were used to put stringent exclusion limits on the new physics models.

scholarly journals Searches for low-mass dimuon resonances

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
R. Aaij ◽  
◽  
C. Abellán Beteta ◽  
T. Ackernley ◽  
B. Adeva ◽  
...  
Keyword(s):  
Cross Sections ◽  
Center Of Mass ◽  
Mass Range ◽  
Higgs Doublet ◽  
Proton Collision ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Lhcb Detector ◽  
Low Mass ◽  
Proton Proton Collision

Abstract Searches are performed for a low-mass dimuon resonance, X, produced in proton-proton collisions at a center-of-mass energy of 13 TeV, using a data sample corresponding to an integrated luminosity of 5.1 fb−1 and collected with the LHCb detector. The X bosons can either decay promptly or displaced from the proton-proton collision, where in both cases the requirements placed on the event and the assumptions made about the production mechanisms are kept as minimal as possible. The searches for promptly decaying X bosons explore the mass range from near the dimuon threshold up to 60 GeV, with nonnegligible X widths considered above 20 GeV. The searches for displaced X → μ+μ− decays consider masses up to 3 GeV. None of the searches finds evidence for a signal and 90% confidence-level exclusion limits are placed on the X → μ+μ− cross sections, each with minimal model dependence. In addition, these results are used to place world-leading constraints on GeV-scale bosons in the two-Higgs-doublet and hidden-valley scenarios.

scholarly journals Measurement of prompt open-charm production cross sections in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Cross Sections ◽  
Theoretical Calculations ◽  
Production Cross ◽  
Center Of Mass ◽  
Open Charm ◽  
Charm Mesons ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
Proton Proton Collisions

Abstract The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13 TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb−1. The differential production cross sections of the D∗±, D±, and D0$$ \left({\overline{\mathrm{D}}}^0\right) $$ D ¯ 0 mesons are presented in ranges of transverse momentum and pseudorapidity 4 < pT< 100 GeV and |η| < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.

scholarly journals VBS W±W±H production at the HL-LHC and a 100 TeV pp-collider

2017 ◽  
Vol 32 (18) ◽  
pp. 1750106 ◽  
Author(s):  
Christoph Englert ◽  
Qiang Li ◽  
Michael Spannowsky ◽  
Mengmeng Wang ◽  
Lei Wang
Keyword(s):  
Direct Evidence ◽  
Vector Boson ◽  
Monte Carlo Study ◽  
New Physics ◽  
Hadron Colliders ◽  
Text Production ◽  
Truncation Scheme ◽  
Charged Leptons ◽  
Vector Boson Scattering ◽  
The Impact

[Formula: see text] production at hadron colliders through vector boson scattering is a so far unconsidered process, which leads to a clean signature of two same-sign charged leptons and two widely separated jets. This process is sensitive to the [Formula: see text] and [Formula: see text] couplings and any deviation of these couplings from their SM predictions serves as direct evidence of new physics beyond the SM. In this paper, we perform a Monte Carlo study of this process for the [Formula: see text] LHC and a 100 TeV [Formula: see text]-collider, and provide projections of the constraints on the triple-Higgs and [Formula: see text] quartic couplings for these environments. In particular, we consider the impact of pileup on the expected sensitivity in this channel. Our analysis demonstrates that although the sensitivity to the [Formula: see text] coupling is rather low, the [Formula: see text] coupling can be constrained in this channel within [Formula: see text][Formula: see text]100% and [Formula: see text][Formula: see text]20% at 95% confidence level around the SM prediction at the HL-LHC and a 100 TeV [Formula: see text]-collider, respectively. We have also provided results with simple truncation scheme, in consideration of unitarity safety.

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