scholarly journals Next-to-Leading Order Differential Cross Sections forJ/ψ,ψ(2S), andΥProduction in Proton-Proton Collisions at a Fixed-Target Experiment Using the LHC Beams

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Yu Feng ◽  
Jian-Xiong Wang
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Differential Cross ◽  
Center Of Mass ◽  
Distance Matrix ◽  
Leading Order ◽  
Fixed Target ◽  
Long Distance ◽  
Center Of Mass Energy ◽  
Central Rapidity

Using nonrelativistic QCD (NRQCD) factorization, we calculate the yields forJ/ψ,ψ(2S), andΥ(1S)hadroproduction ats=72 GeV and 115 GeV including the next-to-leading order QCD corrections. Both these center-of-mass energies correspond to those obtained with 7 TeV and 2.76 TeV nucleon beam impinging a fixed target. We study the cross section integrated inptas a function of the (center-of-mass) rapidity as well as theptdifferential cross section in the central rapidity region. Using different NLO fit results of the NRQCD long-distance matrix elements, we evaluate a theoretical uncertainty which is certainly much larger than the projected experimental uncertainties with the expected 20 fb−1to be collected per year with AFTER@LHC forppcollision at the center of mass energys≃115 GeV.

scholarly journals Coherent $$\mathrm{J}/\psi $$ and $${\uppsi '}$$ photoproduction at midrapidity in ultra-peripheral Pb–Pb  collisions at $$\sqrt{s_{\mathrm {NN}}}~=~5.02$$ TeV

2021 ◽  
Vol 81 (8) ◽  
Author(s):  
◽  
S. Acharya ◽  
D. Adamová ◽  
A. Adler ◽  
J. Adolfsson ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Center Of Mass ◽  
Theoretical Models ◽  
Proton Antiproton ◽  
Decay Channels ◽  
Hadronic Interactions ◽  
Center Of Mass Energy ◽  
Central Rapidity ◽  
The One

AbstractThe coherent photoproduction of $$\mathrm{J}/\psi $$ J / ψ and $${\uppsi '}$$ ψ ′ mesons was measured in ultra-peripheral Pb–Pb collisions at a center-of-mass energy $$\sqrt{s_{\mathrm {NN}}}~=~5.02$$ s NN = 5.02  TeV  with the ALICE detector. Charmonia are detected in the central rapidity region for events where the hadronic interactions are strongly suppressed. The $$\mathrm{J}/\psi $$ J / ψ is reconstructed using the dilepton ($$l^{+} l^{-}$$ l + l - ) and proton–antiproton decay channels, while for the $${\uppsi '}$$ ψ ′   the dilepton and the $$l^{+} l^{-} \pi ^{+} \pi ^{-}$$ l + l - π + π - decay channels are studied. The analysis is based on an event sample corresponding to an integrated luminosity of about 233 $$\mu {\mathrm{b}}^{-1}$$ μ b - 1 . The results are compared with theoretical models for coherent $$\mathrm{J}/\psi $$ J / ψ and $${\uppsi '}$$ ψ ′ photoproduction. The coherent cross section is found to be in a good agreement with models incorporating moderate nuclear gluon shadowing of about 0.64 at a Bjorken-x of around $$6\times 10^{-4}$$ 6 × 10 - 4 , such as the EPS09 parametrization, however none of the models is able to fully describe the rapidity dependence of the coherent $$\mathrm{J}/\psi $$ J / ψ cross section including ALICE measurements at forward rapidity. The ratio of $${\uppsi '}$$ ψ ′ to $$\mathrm{J}/\psi $$ J / ψ coherent photoproduction cross sections was also measured and found to be consistent with the one for photoproduction off protons.

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 Energy dependence of $$\phi $$ meson production at forward rapidity in pp collisions at the LHC

2021 ◽  
Vol 81 (8) ◽  
Author(s):  
S. Acharya ◽  
D. Adamová ◽  
A. Adler ◽  
J. Adolfsson ◽  
G. Aglieri Rinella ◽  
...  
Keyword(s):  
Differential Cross Section ◽  
Energy Dependence ◽  
Cross Section ◽  
Cross Sections ◽  
Differential Cross ◽  
Decay Channel ◽  
Center Of Mass ◽  
Meson Production ◽  
Pp Collisions ◽  
Rapidity Distributions

AbstractThe production of $$\phi $$ ϕ mesons has been studied in pp collisions at LHC energies with the ALICE detector via the dimuon decay channel in the rapidity region $$2.5< y < 4$$ 2.5 < y < 4 . Measurements of the differential cross section $$\mathrm{d}^2\sigma /\mathrm{d}y \mathrm{d}p_{\mathrm {T}}$$ d 2 σ / d y d p T are presented as a function of the transverse momentum ($$p_{\mathrm {T}}$$ p T ) at the center-of-mass energies $$\sqrt{s}=5.02$$ s = 5.02 , 8 and 13 TeV and compared with the ALICE results at midrapidity. The differential cross sections at $$\sqrt{s}=5.02$$ s = 5.02 and 13 TeV are also studied in several rapidity intervals as a function of $$p_{\mathrm {T}}$$ p T , and as a function of rapidity in three $$p_{\mathrm {T}}$$ p T intervals. A hardening of the $$p_{\mathrm {T}}$$ p T -differential cross section with the collision energy is observed, while, for a given energy, $$p_{\mathrm {T}}$$ p T spectra soften with increasing rapidity and, conversely, rapidity distributions get slightly narrower at increasing $$p_{\mathrm {T}}$$ p T . The new results, complementing the published measurements at $$\sqrt{s}=2.76$$ s = 2.76 and 7 TeV, allow one to establish the energy dependence of $$\phi $$ ϕ meson production and to compare the measured cross sections with phenomenological models. None of the considered models manages to describe the evolution of the cross section with $$p_{\mathrm {T}}$$ p T and rapidity at all the energies.

Differential cross-section for 3He4He elastic scattering at 44.5 MeV center-of-mass energy

1971 ◽  
Vol 34 (3) ◽  
pp. 171-173 ◽  
Author(s):  
W. Fetscher ◽  
K. Sattler ◽  
N.C. Schmeing ◽  
E. Seibt ◽  
Ch. Weddigen ◽  
...  
Keyword(s):  
Elastic Scattering ◽  
Differential Cross Section ◽  
Cross Section ◽  
Differential Cross ◽  
Center Of Mass ◽  
Mass Energy ◽  
Center Of Mass Energy

scholarly journals Angular analysis of the e+e- → D(*)D* process near the open-charm threshold using initial-state radiation

2019 ◽  
Vol 202 ◽  
pp. 06008
Author(s):  
Valentina Zhukova
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Center Of Mass ◽  
Initial State Radiation ◽  
Initial State ◽  
Center Of Mass Energy ◽  
Belle Detector ◽  
Section Measurement ◽  
Angular Analysis ◽  
State Radiation

We report new measurement of the exclusive e+e- → D(*)±D*∓ cross sections as a function of center-of-mass energy from the D(∗)±D∗∓ threshold up to $ \sqrt s $ = 6.0 GeV with initial state radiation. The analysis is based on a data sample collected by the Belle detector with an integrated luminosity of 951 fb−1. The accuracy of the cross section measurement is increased by a factor of 2 in comparison with the first Belle study. We have performed the first angular analysis of the e+e- → D∗±D∗∓ process and decomposed this exclusive cross section into three components corresponding to the different D∗ helicities.

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