scholarly journals Charmonium Production in Fermilab E789

1997 ◽  
Vol 12 (22) ◽  
pp. 3827-3836 ◽  
Author(s):  
Daniel M. Kaplan
Keyword(s):  
Perturbative Qcd ◽  
Cross Sections ◽  
Differential Cross ◽  
Production Cross ◽  
Differential Cross Sections ◽  
Color Singlet ◽  
Charmonium Production ◽  
Detailed Understanding ◽  
Color Octet ◽  
Beauty Production

Using a sample of > 105 J/ψ → μ+ μ- decays, Fermilab experiment 789 has studied production of J/ψ and ψ′ in 800 GeV proton-nucleon collisions. Differential cross sections and nuclear dependences have been measured for charmonium as well as for charm and beauty production. While charm and beauty production are consistent with perturbative QCD calculations, charmonium cross sections exceed the predictions of the color-singlet model by large factors, suggesting that additional mechanisms (such as color-octet production) may play important roles. Nuclear dependences of production cross sections may offer a new tool for the detailed understanding of charmonium production.

scholarly journals Measurement of differential cross sections for Z bosons produced in association with charm jets in pp collisions at $$ \sqrt{s} $$ = 13 TeV

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Z Boson ◽  
Production Cross ◽  
Charm Quark ◽  
Z Bosons ◽  
Monte Carlo Event ◽  
Differential Cross Sections ◽  
Pp Collisions ◽  
Proton Proton

Abstract Measurements are presented of differential cross sections for the production of Z bosons in association with at least one jet initiated by a charm quark in pp collisions at $$ \sqrt{s} $$ s = 13 TeV. The data recorded by the CMS experiment at the LHC correspond to an integrated luminosity of 35.9 fb−1. The final states contain a pair of electrons or muons that are the decay products of a Z boson, and a jet consistent with being initiated by a charm quark produced in the hard interaction. Differential cross sections as a function of the transverse momentum pT of the Z boson and pT of the charm jet are compared with predictions from Monte Carlo event generators. The inclusive production cross section 405.4 ± 5.6 (stat) ± 24.3 (exp) ± 3.7 (theo) pb, is measured in a fiducial region requiring both leptons to have pseudorapidity |η| < 2.4 and pT> 10 GeV, at least one lepton with pT> 26 GeV, and a mass of the pair in the range 71–111 GeV, while the charm jet is required to have pT> 30 GeV and |η| < 2.4. These are the first measurements of these cross sections in proton-proton collisions at 13 TeV.

scholarly journals Measurement of the production cross section of pairs of isolated photons in pp collisions at 13 TeV with the ATLAS detector

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
◽  
G. Aad ◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Cross Sections ◽  
Differential Cross ◽  
Production Cross ◽  
Atlas Detector ◽  
Differential Cross Sections ◽  
Proton Proton ◽  
Theoretical Predictions ◽  
Fixed Order ◽  
Isolated Photons

Abstract A measurement of prompt photon-pair production in proton-proton collisions at $$ \sqrt{s} $$ s = 13 TeV is presented. The data were recorded by the ATLAS detector at the LHC with an integrated luminosity of 139 fb−1. Events with two photons in the well-instrumented region of the detector are selected. The photons are required to be isolated and have a transverse momentum of $$ {p}_{\mathrm{T}{,}_{\gamma 1(2)}} $$ p T , γ 1 2 > 40 (30) GeV for the leading (sub-leading) photon. The differential cross sections as functions of several observables for the diphoton system are measured and compared with theoretical predictions from state-of-the-art Monte Carlo and fixed-order calculations. The QCD predictions from next-to-next-to-leading-order calculations and multi-leg merged calculations are able to describe the measured integrated and differential cross sections within uncertainties, whereas lower-order calculations show significant deviations, demonstrating that higher-order perturbative QCD corrections are crucial for this process. The resummed predictions with parton showers additionally provide an excellent description of the low transverse-momentum regime of the diphoton system.

scholarly journals High Order QCD Predictions for Inclusive Production ofWBosons inppCollisions ats=13 TeV

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Hasan Ogul ◽  
Kamuran Dilsiz ◽  
Emrah Tiras ◽  
Ping Tan ◽  
Yasar Onel ◽  
...  
Keyword(s):  
Perturbative Qcd ◽  
Cross Section ◽  
Cross Sections ◽  
Differential Cross ◽  
Charge Asymmetry ◽  
Inclusive Production ◽  
Differential Cross Sections ◽  
Leading Order ◽  
Central Values ◽  
Lepton Charge

Predictions of fiducial cross sections, differential cross sections, and lepton charge asymmetry are presented for the production ofW±bosons with leptonic decay up to next-to-next-to-leading order (NNLO) in perturbative QCD. Differential cross sections ofW±bosons andWboson lepton charge asymmetry are computed as a function of lepton pseudorapidity for a defined fiducial region inppcollisions ats=13 TeV. Numerical results of fiducialW±cross section predictions are presented with the latest modern PDF models at next-to-leading order (NLO) and NNLO. It is found that the CT14 and NNPDF 3.0 predictions with NNLO QCD corrections are about 4% higher than the NLO CT14 and NNPDF 3.0 predictions while MMHT 2014 predictions with NLO QCD corrections are smaller than its NNLO QCD predictions by approximately 6%. In addition, the NNLO QCD corrections reduce the scale variation uncertainty on the cross section by a factor of 3.5. The prediction of central values and considered uncertainties are obtained using FEWZ 3.1 program.

Charmonium Production in 800 GeV/c p-Si Interactions

1997 ◽  
Vol 12 (22) ◽  
pp. 3847-3855
Author(s):  
Karla Hagan
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Differential Cross Sections ◽  
Fixed Target ◽  
Charmonium Production

Charmonium results are presented from Fermilab Experiment 771, proton-silicon interactions at [Formula: see text] with a fixed target spectrometer and dimuon trigger. Total and differential cross sections for J/ψ and ψ(2S) will be discussed, as well as a preliminary result on χ production.

scholarly journals CHARMONIUM PRODUCTION AT HERA

2007 ◽  
Vol 22 (02n03) ◽  
pp. 455-463
Author(s):  
ANDREAS B. MEYER
Keyword(s):  
Quantum Chromodynamics ◽  
Cross Sections ◽  
Relativistic Quantum ◽  
Gluon Fusion ◽  
Color Singlet ◽  
Charmonium Production ◽  
Color Octet ◽  
The Cross

Measurements of Charmonium production at the electron proton collider HERA are presented. In inelastic production the charmonium is formed from [Formula: see text] pairs that are produced in photon gluon fusion. The measurements of the cross sections and helicity distributions are compared to calculations performed in the framework of non-relativistic quantum chromodynamics (NRQCD), which includes both color-singlet and color-octet contributions.

Charmonium Production with 300 GeV/c π+, π-, p and $\bar{p}$ Beams

1997 ◽  
Vol 12 (22) ◽  
pp. 3837-3846
Author(s):  
Michael Arenton
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Differential Cross Sections ◽  
Direct Production ◽  
Charmonium Production ◽  
Charmonium States

Results of an experiment measuring the production of charmonium states with 300 GeV/c π+, π-, p and [Formula: see text] beams on a Li target are presented. Total and differential cross sections for production of J/ψ, ψ′ and χ states are presented. The separation of the χ signal into the χ1 and χ2 states is discussed. The fraction of J/ψ's that result from direct production is derived.

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