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Towards the construction of the ATLAS ITk Pixel innermost layer
No full textA massive upgrade is scheduled for the ATLAS tracking system to face the High-Luminosity program of the Large Hadron Collider. The ATLAS current Inner Detector will be fully replaced by a new all-silicon tracker, the so-called Inner Tracker (ITk), made by Pixel and Strip detectors. This paper aims to focus on the characterization of the pixel modules for the ITk Pixel detector innermost layer. This layer, placed at 34 mm from the beamline, will play a crucial role in the tracker performance. The paper will report on the results of the assembly procedure in the production sites, quality control and quality assurance of the pixel modules assembly and testing, mainly focusing on the bump-bonding connection quality, which has been validated through dedicated bumps delamination studies
Study of semileptonic vector boson scattering and anomalous quartic gauge coupling from proton-proton collisions at 13 TeV
No full textA measurement of the electroweak production of ZV (V = W, Z) boson pairs associated with two jets in proton-proton collisions at a center-of-mass energy of 13 TeV is presented. The analysis targets final states with two isolated electrons or muons from Z decays and three to four jets, depending on the momentum of the vector boson that decays into quarks. The data, corresponding to an integrated luminosity of 138 fb, were collected at the CERN LHC with the CMS detector during the 2016--2018 data-taking period.
The cross section is measured in a fiducial region characterized by a large invariant mass and pseudorapidity gap between the two forward jets. The electroweak production of ZV in association with two jets is measured with an observed (expected) significance of 1.3 (1.8) standard deviations. Constraints are also placed on effective field theory parameters that describe anomalous electroweak production of WW, WZ, and ZZ boson pair pairs in association with two jets, combining the ZV and WV semileptonic events. Stringent limits are set on anomalous quartic gauge couplings in terms of dimension-8 operators
Searches for electroweak production of supersymmetric particles with the ATLAS detector
No full textThe direct production of electroweak SUSY particles, including sleptons, charginos, and neutralinos, is a particularly interesting area with connections to dark matter and the naturalness of the Higgs mass. The small production cross-sections and challenging experimental signatures, often involving compressed spectra, lead to difficult searches. This talk will highlight the most recent results of searches performed by the ATLAS experiment for supersymmetric particles produced via electroweak processes, including analyses targeting small mass splittings between SUSY particles, and including both in R-parity-conserving and R-parity-violating scenarios. Recent results involving the combination of searches are also presented
Study of the Damage Potential of the FCC-ee Beams
No full textThe beam characteristics of the Future Circular Collider electron-positron (FCC-ee) beam differ vastly from those of the Large Hadron Collider (LHC) beam and the High Luminosity LHC (HL-LHC) beam, presenting new challenges for assessing beam impact and damage potential. The FCC-ee consist of electrons with significantly lower energies than the protons in the LHC and HL-LHC beams. In the Z~mode, the total stored beam energy will be 17.5 MJ, while the same values for the LHC and HL-LHC beams are 362 MJ and 681 MJ, respectively. The FCC-ee beams will also operate with a highly asymmetric emittance (), while the LHC and HL-LHC beams can be approximated as round. This report presents the stored beam energy and analytical estimations for the energy density of the FCC-ee beams, considering a range of beam sizes, and compares them with the LHC and HL-LHC beams. Then, energy deposition of the generic scenario of a direct beam impact on a graphite target with nominal material density is simulated using FLUKA. Results show that the peak energy depositions for the FCC-ee beams with Z~mode parameters are comparable to those of the LHC and HL-LHC beams. However, the shape of the energy deposition shower is more peaked and localized close to the beam impact point. In the last step, the hydrodynamic response of the material due to the impact of a round beam with a corresponding peak energy deposition is analyzed. After the impact of five bunches, it is observed a maximum energy deposition and temperature rise comparable to those due to the impact of the HL-LHC beam with a beam size of = 0.5 mm. However, the local target density depletes more rapidly
Highlights on top quark physics with the ATLAS experiment at the LHC
No full textThe large top-quark samples collected with the ATLAS experiment at the LHC together with a unprecedented understanding of the measured data have yielded measurements of production cross-sections for top-quark pair-production not only in new kinematic regions but also in association with additional quarks and boson. Searches for rare top-quark decays or new physics processes in the top-quark sector are possible with the highest precision as well as measurements using proton-lead collision. In this contribution the highlights of the ATLAS top-quark physics program are presented
LumiDays 25
No full textSummary of the beam-beam papers, with the emphasis on
(i) bb-related vdM uncertainties as currently understood, and
(ii) pending issue
LumiDays 25
No full text2-D vdM, beam-beam imaging and LRE analyses
• Including CMS results from the NF MD
LumiDays 25
No full text2-D vdM and LRE analyses
• Including ATLAS results from the NF MD?
• Include some ALICE LRE results if so requeste
Measurements of the inclusive W and Z boson production cross sections and their ratios in proton-proton collisions at 13.6 TeV
No full textMeasurements are presented of the W and Z boson production cross sections in proton-proton collisions at a center-of-mass energy of 13.6 TeV. Data collected in 2022 and corresponding to an integrated luminosity of 5.01 fb with one or two identified muons in the final state are analyzed. The results for the products of total inclusive cross sections and branching fractions for muonic decays of W and Z bosons are 11.93 0.08 (syst) 0.17 (lumi) (acceptance) nb for boson production, 8.86 0.06 (syst) 0.12 (lumi) (acceptance) nb for boson production, and 2.021 0.009 (syst) 0.028 (lumi) (acceptance) nb for the Z boson production in the dimuon mass range of 60--120 GeV, all with negligible statistical uncertainties. Furthermore, the corresponding fiducial cross sections, as well as cross section ratios for both fiducial and total phase space, are provided. The ratios include charge-separated results for W boson production ( and ) and the sum of the two contributions (), each relative to the measured Z boson production cross section. Additionally, the ratio of the measured cross sections for and boson production is reported. All measurements are in agreement with theoretical predictions, calculated at next-to-next-to-leading order accuracy in quantum chromodynamics.Measurements are presented of the W and Z boson production cross sections in proton-proton collisions at a center-of-mass energy of 13.6 TeV. Data collected in 2022 and corresponding to an integrated luminosity of 5.01 fb with one or two identified muons in the final state are analyzed. The results for the products of total inclusive cross sections and branching fractions for muonic decays of W and Z bosons are 11.93 0.08 (syst) 0.17 (lumi) (acc) nb for W boson production, 8.86 0.06 (syst) 0.12 (lumi) (acc) nb for W boson production, and 2.021 0.009 (syst) 0.028 (lumi) (acc) nb for the Z boson production in the dimuon mass range of 60-120 GeV, all with negligible statistical uncertainties. Furthermore, the corresponding fiducial cross sections, as well as cross section ratios for both fiducial and total phase space, are provided. The ratios include charge-separated results for W boson production (W and W) and the sum of the two contributions (W), each relative to the measured Z boson production cross section. Additionally, the ratio of the measured cross sections for W and W boson production is reported. All measurements are in agreement with theoretical predictions, calculated at next-to-next-to-leading order accuracy in quantum chromodynamics
Constraining the Top-Higgs Yukawa Coupling with Production at TeV with CMS Experiment
No full textA measurement of the top quark Yukawa coupling from the t¯t differential production cross sections in the semi-leptonic channel is presented. The t¯t production cross
section is sensitive to the square of the Yukawa coupling via weak corrections that enter when Higgs bosons are exchanged between the final state top and anti-top quarks. These weak corrections have a negligible effect in the inclusive t¯t produc-
tion cross section, but they lead to strong distortions of differential distributions near the threshold energy for pair-production (for low relative velocities of the top quarks). The differential distributions are therefore sensitive to anomalous values of the top Yukawa coupling and allow us to set an upper limit based on precision measurements.
This analysis is based on data collected by the CMS experiment in the LHC
at 13 TeV corresponding to an integrated luminosity of 35.8 fb 1. In addition to
a top reconstruction with at least four jets in the final state, a novel technique to reconstruct the t¯t system with one missing jet is developed to enhance the
experimental sensitivity in the low invariant mass region. We compare the data yields in the invariant mass of the top-antitop system, Mt¯t, the rapidity difference between top and antitop, |yt y¯t|, and the number of reconstructed jets with the templates simulated for different values of the top Yukawa coupling and extract an upper limit on the top quark Yukawa coupling of 1.62 (Expected) at 95% CL