scholarly journals Sensitivity on anomalous neutral triple gauge couplings via ZZ production at FCC-hh

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
A. Yilmaz ◽  
A. Senol ◽  
H. Denizli ◽  
I. Turk Cakir ◽  
O. Cakir

Abstract We study the sensitivity of anomalous neutral triple gauge couplings (aNTGC) via $$pp \rightarrow ZZ$$pp→ZZ production in the 4$$\ell $$ℓ channel at 100 TeV center of mass energy of future circular hadron collider, . The analysis including the realistic detector effects is performed in the mode where both Z bosons decay into same-flavor, oppositely charged lepton pairs. The sensitivities to the charge–parity (CP)-conserving couplings $$C_{{\tilde{B}}W} / \Lambda ^{4}$$CB~W/Λ4 and CP-violating couplings $$C_{WW} / \Lambda ^{4}$$CWW/Λ4, $$C_{BW} / \Lambda ^{4}$$CBW/Λ4 and $$C_{BB} / \Lambda ^{4}$$CBB/Λ4 obtained at 95% Confidence Level using the invariant mass distribution of the 4$$\ell $$ℓ system reconstructing the leading and sub-leading Z boson candidates are $$[-\,0.09, \,\, +\,0.09]$$[-0.09,+0.09], $$[-\,0.21, \,\, +\,0.21]$$[-0.21,+0.21], $$[-\,0.26, \,\, +\,0.26]$$[-0.26,+0.26], and $$[-\,0.10, \,\, +\,0.10]$$[-0.10,+0.10] in units of $$\hbox {TeV}^{-4}$$TeV-4, respectively.

2021 ◽  
Vol 81 (3) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  

AbstractThe production of Z boson pairs in proton–proton ($${\mathrm{p}} {\mathrm{p}} $$ p p ) collisions, $${{\mathrm{p}} {\mathrm{p}} \rightarrow ({\mathrm{Z}}/\gamma ^*)({\mathrm{Z}}/\gamma ^*) \rightarrow 2\ell 2\ell '}$$ p p → ( Z / γ ∗ ) ( Z / γ ∗ ) → 2 ℓ 2 ℓ ′ , where $${\ell ,\ell ' = {\mathrm{e}}}$$ ℓ , ℓ ′ = e or $${{\upmu }}$$ μ , is studied at a center-of-mass energy of 13$$\,\text {TeV}$$ TeV with the CMS detector at the CERN LHC. The data sample corresponds to an integrated luminosity of 137$$\,\text {fb}^{-1}$$ fb - 1 , collected during 2016–2018. The $${\mathrm{Z}} {\mathrm{Z}} $$ Z Z production cross section, $$\sigma _{\text {tot}} ({\mathrm{p}} {\mathrm{p}} \rightarrow {\mathrm{Z}} {\mathrm{Z}} ) = 17.4 \pm 0.3 \,\text {(stat)} \pm 0.5 \,\text {(syst)} \pm 0.4 \,\text {(theo)} \pm 0.3 \,\text {(lumi)} \text { pb} $$ σ tot ( p p → Z Z ) = 17.4 ± 0.3 (stat) ± 0.5 (syst) ± 0.4 (theo) ± 0.3 (lumi) pb , measured for events with two pairs of opposite-sign, same-flavor leptons produced in the mass region $${60< m_{\ell ^+\ell ^-} < 120\,\text {GeV}}$$ 60 < m ℓ + ℓ - < 120 GeV is consistent with standard model predictions. Differential cross sections are also measured and agree with theoretical predictions. The invariant mass distribution of the four-lepton system is used to set limits on anomalous $${\mathrm{Z}} {\mathrm{Z}} {\mathrm{Z}} $$ Z Z Z and $${{\mathrm{Z}} {\mathrm{Z}} \gamma }$$ Z Z γ couplings.


2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
◽  
A. M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  

Abstract Measurements of the differential cross sections of Z + jets and γ + jets production, and their ratio, are presented as a function of the boson transverse momentum. Measurements are also presented of the angular distribution between the Z boson and the closest jet. The analysis is based on pp collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 35.9 fb−1 recorded by the CMS experiment at the LHC. The results, corrected for detector effects, are compared with various theoretical predictions. In general, the predictions at higher orders in perturbation theory show better agreement with the measurements. This work provides the first measurement of the ratio of the differential cross sections of Z + jets and γ + jets production at 13 TeV, as well as the first direct measurement of Z bosons emitted collinearly with a jet.


2015 ◽  
Vol 30 (22) ◽  
pp. 1550131 ◽  
Author(s):  
A. Tawfik ◽  
E. Gamal ◽  
A. G. Shalaby

The production of pion, kaon and proton was measured in Pb–Pb collisions at nucleus–nucleus center-of-mass energy [Formula: see text] by the ALICE experiment at Large Hadron Collider (LHC). The particle ratios of these species compared to the RHIC measurements are confronted to the hadron resonance gas (HRG) model and to simulations based on the event generators PYTHIA 6.4.21 and HIJING 1.36. It is found that the homogeneous particle–antiparticle ratios (same species) are fully reproducible by means of HRG and partly by PYTHIA 6.4.21 and HIJING 1.36. The mixed kaon–pion and proton–pion ratios measured at RHIC and LHC energies seem to be reproducible by the HRG model. On the other hand, the strange abundances are underestimated in both event generators. This might be originated to strangeness suppression in the event generators and/or possible strangeness enhancement in the experimental data. It is apparent that the values of kaon–pion ratios are not sensitive to the huge increase of [Formula: see text] from 200 (RHIC) to 2760 GeV (LHC). We conclude that the ratios of produced particle at LHC seem not depending on the system size.


2020 ◽  
Vol 241 ◽  
pp. 01007
Author(s):  
Takatsugu Ishikawa ◽  
Hisako Fujimura ◽  
Hiroshi Fukasawa ◽  
Ryo Hashimoto ◽  
Qinghua He ◽  
...  

The B = 2 bound/resonance state (dibaryon) is an interesting object, which can be a molecule consisting of two baryons or a spatially compact hexaquark hadron object. The yd ^ n°n°d reaction has been experimentally investigated at incident energies ranging from 0.58 to 1.15 GeV to study non-strange dibaryons. The angular distributions of deuteron emission in the yd center-of-mass energy cannot be reproduced by quasi-free production of two neutral pions followed by deuteron coalescence. Additionally a 2.14-GeV peak is observed in the n°d invariant mass distribution. These suggest a sequential process such as yd ^ RIS ^ n°RIV ^ n°n°d with an isoscalar dibaryon RIS and an isovector dibaryon RIV. Since the mass of the observed isoscalar dibaryons are close to the sum of the nucleon (N) and nucleon resonance (N*) masses, an S-wave NN* molecule may play a role as a doorway to a dibaryon.


2013 ◽  
Vol 28 (26) ◽  
pp. 1330038 ◽  
Author(s):  
SHABNAM JABEEN

This review summarizes the recent results for top quark and Higgs boson measurements from experiments at Tevatron, a proton–antiproton collider at a center-of-mass energy of [Formula: see text], and the Large Hadron Collider, a proton–proton collider at a center-of-mass energy of [Formula: see text]. These results include the discovery of a Higgs-like boson and measurement of its various properties, and measurements in the top quark sector, e.g. top quark mass, spin, charge asymmetry and production of single top quark.


2014 ◽  
Vol 31 ◽  
pp. 1460279 ◽  
Author(s):  
Jian Wang ◽  

This is a report at the conference Physics In Collision 2013. The experimental results on physics of diboson production are reviewed. The measurements use pp collision at the LHC with center-of-mass energy [Formula: see text] and 8 TeV, and [Formula: see text] collision at the Tevatron with [Formula: see text]. These include measurements of Wγ, Zγ, WW, WZ and ZZ production. The results are compared with Standard Model predictions, and are interpreted in terms of constraints on charged and neutral anomalous triple gauge couplings.


2015 ◽  
Vol 30 (34) ◽  
pp. 1530061 ◽  
Author(s):  
Douglas M. Gingrich

The possibility of producing nonperturbative low-scale gravity states in collider experiments was first discussed in about 1998. The ATLAS and CMS experiments have searched for nonperturbative low-scale gravity states using the Large Hadron Collider with a proton–proton center-of-mass energy of 8 TeV. These experiments have now seriously confronted the possibility of producing nonperturbative low-scale gravity states which were proposed over 17 years ago. I will summarize the results of the searches, give a personal view of what they mean, and make some predictions for 13 TeV center-of-mass energy. I will also discuss early ATLAS 13 TeV center-of-mass energy results.


2020 ◽  
Vol 35 (36) ◽  
pp. 2050302
Author(s):  
Amr Radi

With many applications in high-energy physics, Deep Learning or Deep Neural Network (DNN) has become noticeable and practical in recent years. In this article, a new technique is presented for modeling the charged particles multiplicity distribution [Formula: see text] of Proton-Proton [Formula: see text] collisions using an efficient DNN model. The charged particles multiplicity n, the total center of mass energy [Formula: see text], and the pseudorapidity [Formula: see text] used as input in DNN model and the desired output is [Formula: see text]. DNN was trained to build a function, which studies the relationship between [Formula: see text]. The DNN model showed a high degree of consistency in matching the data distributions. The DNN model is used to predict with [Formula: see text] not included in the training set. The expected [Formula: see text] had effectively merged the experimental data and the values expected indicate a strong agreement with Large Hadron Collider (LHC) for ATLAS measurement at [Formula: see text], 7 and 8 TeV.


Universe ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 11
Author(s):  
Carla Sbarra ◽  

LUCID (LUminosity Cerenkov Integrating Detector) is the main luminosity monitor of the ATLAS (A Toroidal LHC Apparatus) experiment at the Large Hadron Collider (LHC) and in particular is the only one capable of providing bunch-by-bunch luminosity information, both online and offline, for all beam conditions and luminosity ranges. LUCID-2 refers to the detector upgrade designed to cope with the running conditions to be met in Run-2 (2015–2018): a center of mass energy of 13 TeV, with 50 pp interactions per bunch-crossing on average and a 25 ns bunch-spacing. This report summarizes all changes with respect to the detector deployed in Run-1 (2010–2012), including smaller sensors for higher granularity, new readout electronics for early signal digitization, and a completely new calibration concept guaranteeing long-term stability of the detector response. In addition, the overall detector performance in Run-2 and preliminary results on luminosity measurements are presented.


2007 ◽  
Vol 16 (07n08) ◽  
pp. 1917-1922
Author(s):  
D. KROFCHECK ◽  
R. MAK ◽  
P. ALLFREY

At the Relativistic Heavy Ion Collider (RHIC) elliptic flow signals (v2) appear to be stronger than those measured at lower center-of-mass energies. With the beginning of heavy ion beams at the Large Hadron Collider (LHC) it is important to have a reliable tool for simulating v2 at the LHC Pb – Pb center-of-mass energy of 5.5 A TeV. In this work we used the heavy ion simulation tool HYDJET to study elliptic flow at the event generator level. The generator level elliptic flow v2 for Pb – Pb collisions was two-particle and four-particle cumulants.


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