A-DEPENDENCE OF Z-SCALING

2001 ◽  
Vol 16 (07) ◽  
pp. 1281-1301 ◽  
Author(s):  
M. V. TOKAREV ◽  
Yu. A. PANEBRATSEV ◽  
I. ZBOROVSKÝ ◽  
G. P. ŠKORO
Keyword(s):  
Cross Sections ◽  
Particle Production ◽  
Center Of Mass ◽  
Nucleon Nucleon ◽  
Hadron Production ◽  
Scale Transformation ◽  
Invariant Cross Section ◽  
Center Of Mass Energy ◽  
Energy Formula ◽  
Nucleon Nucleon Interaction

The A-dependence of z-scaling in inclusive hadron production in pA collisions at high transverse momenta is studied. The concept of z-scaling based on the fundamental principles of Nature such as self-similarity, locality, scale relativity and fractality reflecting the general features of particle interactions is applied for the description of processes of hadron production in pA collisions. The scaling function ψ is expressed via the invariant cross-section Ed3σ/dq3 and the average multiplicity density dN/dη of particles produced at pseudorapidity η=0 in the corresponding nucleon–nucleon interaction. The independence of the function ψ(z) on the center-of-mass energy [Formula: see text] for particle production near 90° in the NN c.m. system for different nuclei from D up to Pb is shown. The scale transformation z→az, ψ→a-1ψ is used to determine the A-dependence of the transformation parameter a. Based on the properties of z-scaling the dependence of the cross-sections for the π±, K±, and [Formula: see text] hadrons produced in pA collisions on transverse momentum q⊥ in the central region (η=0) at RHIC energies is predicted.

scholarly journals Particle production at RHIC and LHC energies

2015 ◽  
Vol 30 (22) ◽  
pp. 1550131 ◽  
Author(s):  
A. Tawfik ◽  
E. Gamal ◽  
A. G. Shalaby
Keyword(s):  
Particle Production ◽  
Hadron Collider ◽  
Center Of Mass ◽  
System Size ◽  
Alice Experiment ◽  
Center Of Mass Energy ◽  
Particle Ratios ◽  
Strangeness Enhancement ◽  
Homogeneous Particle ◽  
Energy Formula

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.

Giant dipole resonance in 4He

1980 ◽  
Vol 58 (11) ◽  
pp. 1555-1559 ◽  
Author(s):  
J. J. Bevelacqua
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Giant Dipole Resonance ◽  
Reasonable Agreement ◽  
Center Of Mass ◽  
Nucleon Nucleon ◽  
Nucleon Interaction ◽  
R Matrix ◽  
Dipole Resonance ◽  
Nucleon Nucleon Interaction

The 4He giant dipole resonance is calculated with the generalized R-matrix method of Lane and Robson. The model treats the center of mass correctly and includes noncentral components in the nucleon–nucleon interaction via the Sussex interaction. The 4He(γ,p)3H and 4He(γ,n)3He cross sections are sensitive to the 4He level spectrum, but are in reasonable agreement with the photonuclear data for level schemes which agree with the spectrum suggested by Fiarman and Meyerhof (FM). Other spectra which bracket the FM levels lead to poorer photonuclear cross sections. R-matrix model results also lead to a (γ,p)/(γ,n) cross section ratio which is about unity.

scholarly journals Target Single-Spin Asymmetry in Inclusive Hadron Production

2015 ◽  
Vol 37 ◽  
pp. 1560067
Author(s):  
Xiaodong Jiang
Keyword(s):  
Spin Asymmetry ◽  
Center Of Mass ◽  
Hadron Production ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Center Of Mass Energy ◽  
Average Momentum ◽  
Single Spin Asymmetries ◽  
Energy Formula ◽  
Effective Neutron

We present the first measurement of target single-spin asymmetries (AN) in the inclusive hadron production reaction, e+3 He ↑ →h+X, using a transversely polarized 3 He target at an electron-nucleon center-of-mass energy [Formula: see text] GeV. The experiment was conducted at Jefferson Lab in Hall A using a 5.9-GeV electron beam. Several types of hadrons (π±, K± and proton) were detected with an average momentum 〈Ph〉 = 2.35 GeV/c, and an average transverse momentum 〈pT〉 = 0.64 GeV/c. The observed asymmetry strongly depends on the type of hadron. A positive asymmetry is observed for π+ and K+. A negative asymmetry is observed for π-. The π+ and π- asymmetries measured for the 3 He target and extracted the "effective- neutron" SSA. Amazingly, we found that the ratio of our observed SSA between π+ and π- productions closely resemble the ratio of up- to down-quark's contributions to neutron's anomalous magnetic moment.

scholarly journals ELECTROWEAK CORRECTIONS TO THE NEUTRALINO PAIR PRODUCTION AT CERN LHC

2013 ◽  
Vol 28 (17) ◽  
pp. 1350077 ◽  
Author(s):  
A. I. AHMADOV ◽  
M. DEMIRCI
Keyword(s):  
Pair Production ◽  
Cross Sections ◽  
Center Of Mass ◽  
Percent Level ◽  
Proton Collision ◽  
Mass Energy ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Energy Formula ◽  
Proton Proton Collision

We apply the leading and subleading electroweak (EW) corrections to the Drell–Yan process of the neutralino pair production at proton–proton collision, in order to calculate the effects of these corrections on the neutralino pair production at the LHC. We provide an analysis of the dependence of the Born cross-sections for [Formula: see text] and the EW corrections to this process, on the center-of-mass energy [Formula: see text], on the M2–μ mass plane and on the squark mass for the three different scenarios. The numerical results show that the relative correction can be reached to the few tens of percent level as the increment of the center-of-mass energy, and the evaluation of EW corrections is a crucial task for all accurate measurements of the neutralino pair production processes.

scholarly journals Measurements of the differential cross sections of the production of Z + jets and γ + jets and of Z boson emission collinear with a jet in pp collisions at $$ \sqrt{s} $$ = 13 TeV

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
◽  
A. M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Z Boson ◽  
Center Of Mass ◽  
Z Bosons ◽  
Differential Cross Sections ◽  
Pp Collisions ◽  
Center Of Mass Energy ◽  
Cms Experiment ◽  
Theoretical Predictions

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.

scholarly journals Diboson production at LHC and Tevatron

2014 ◽  
Vol 31 ◽  
pp. 1460279 ◽  
Author(s):  
Jian Wang ◽  
Keyword(s):  
Standard Model ◽  
Center Of Mass ◽  
Mass Energy ◽  
Diboson Production ◽  
Center Of Mass Energy ◽  
Triple Gauge Couplings ◽  
Model Predictions ◽  
Energy Formula ◽  
Anomalous Triple Gauge Couplings ◽  
8 Tev

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.

scholarly journals Experimental measurement of the 12C+16O fusion cross sections at astrophysical energies

2018 ◽  
Vol 178 ◽  
pp. 04008
Author(s):  
X. Fang ◽  
W. P. Tan ◽  
M. Beard ◽  
R. J. deBoer ◽  
G. Gilardy ◽  
...  
Keyword(s):  
Cross Sections ◽  
Center Of Mass ◽  
Model Calculations ◽  
Center Of Mass Energy ◽  
Pure Graphite ◽  
S Factor ◽  
Hpge Detectors ◽  
Low Energies ◽  
The University

The total cross sections of the 12C+16O fusion have been experimentally determined at low energies to investigate the role of this reaction during late stellar evolution burning phases. A high-intensity oxygen beam was produced by the 5MV pelletron accelerator at the University of Notre Dame impinging on a thick ultra-pure graphite target. Protons and γ-rays were measured simultaneously in the center-of-mass energy range from 3.64 to 5.01 MeV, using strip silicon and HPGe detectors. Statistical model calculations were employed to interpret the experimental results. A new broad resonance-like structure is observed for the 12C+16O reaction, and a decreasing trend of its S-factor towards low energies is found.

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.

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