scholarly journals STRUCTURE FUNCTIONS

2009 ◽  
Vol 24 (06) ◽  
pp. 1069-1086 ◽  
Author(s):  
CRISTINEL DIACONU
Keyword(s):  
Cross Sections ◽  
Structure Functions ◽  
Distribution Functions ◽  
Final States ◽  
Parton Distribution Functions ◽  
Proton Antiproton ◽  
Proton Proton ◽  
Proton Collisions ◽  
Bjorken X ◽  
Proton Proton Collisions

Recent progress in the understanding of the nucleon is presented. The unpolarized structure functions are obtained with unprecedented precision from the combined H1 and ZEUS data and are used to extract proton parton distribution functions via NLO QCD fits. The obtained parametrization displays an improved precision, in particular at low Bjorken x, and leads to precise predictions of cross-sections for LHC phenomena. Recent data from proton–antiproton collisions at Tevatron indicate further precise constraints at large Bjorken x. The flavor content of the proton is further studied using final states with charm and beauty in DIS ep and [Formula: see text] collisions. Data from polarized DIS or proton–proton collisions are used to test the spin structure of the proton and to constrain the polarized parton distributions.

scholarly journals Measurement of the cross-section and charge asymmetry of W bosons produced in proton–proton collisions at $$\sqrt{s}=8~\text {TeV}$$ with the ATLAS detector

2019 ◽  
Vol 79 (9) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
O. Abdinov ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Charge Asymmetry ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Proton Proton ◽  
Proton Collisions ◽  
The Cross ◽  
Proton Proton Collisions ◽  
Integrated Luminosity

Abstract This paper presents measurements of the $$W^+ \rightarrow \mu ^+\nu $$W+→μ+ν and $$W^- \rightarrow \mu ^-\nu $$W-→μ-ν cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton–proton collisions at a centre-of-mass energy of 8 $$\text {TeV}$$TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of $$20.2~\text{ fb }^{-1}$$20.2fb-1. The precision of the cross-section measurements varies between 0.8 and 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.

scholarly journals SQUARK AND GLUINO HADROPRODUCTION

2011 ◽  
Vol 26 (16) ◽  
pp. 2637-2664 ◽  
Author(s):  
WIM BEENAKKER ◽  
SILJA BRENSING ◽  
MICHAEL KRÄMER ◽  
ANNA KULESZA ◽  
ERIC LAENEN ◽  
...  
Keyword(s):  
Cross Sections ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Proton Proton ◽  
Proton Collisions ◽  
Numerical Predictions ◽  
Theoretical Status ◽  
Higher Order Corrections ◽  
The Impact ◽  
Proton Proton Collisions

We review the theoretical status of squark and gluino hadroproduction and provide numerical predictions for all squark and gluino pair-production processes at the Tevatron and at the LHC, with a particular emphasis on proton–proton collisions at 7 TeV. Our predictions include next-to-leading order supersymmetric QCD corrections and the resummation of soft gluon emission at next-to-leading-logarithmic accuracy. We discuss the impact of the higher-order corrections on total cross-sections, and provide an estimate of the theoretical uncertainty due to scale variation and the parton distribution functions.

scholarly journals Production of massless bottom jets in pp̄ and pp collisions at next-to-leading order of QCD

2016 ◽  
Vol 31 (17) ◽  
pp. 1650098
Author(s):  
Isabella Bierenbaum ◽  
Gustav Kramer
Keyword(s):  
Cross Sections ◽  
Leading Order ◽  
Proton Antiproton ◽  
Proton Proton ◽  
Proton Collisions ◽  
Monte Carlo Calculations ◽  
A Value ◽  
Cross Section Formula ◽  
Jet Cross Sections ◽  
Proton Proton Collisions

We present predictions for the inclusive production of bottom jets in proton–antiproton collisions at 1.96 TeV and proton–proton collisions at 7 TeV. The bottom quark is considered massless. In this scheme, we find that at small transverse momentum [Formula: see text] the ratio of the next-to-leading order to the leading-order cross-section ([Formula: see text] factor) is smaller than one. It increases with increasing [Formula: see text] and approaches one at larger [Formula: see text] at a value depending essentially on the choice of the renormalization scale. Adding nonperturbative corrections obtained from PYTHIA Monte Carlo calculations leads to reasonable agreement with experimental [Formula: see text]-jet cross-sections obtained by the CDF and the CMS collaborations.

scholarly journals Production of massless charm jets in pp collisions at next-to-leading order of QCD

2015 ◽  
Vol 30 (18n19) ◽  
pp. 1550111 ◽  
Author(s):  
Isabella Bierenbaum ◽  
Gustav Kramer
Keyword(s):  
Transverse Momentum ◽  
Parton Distribution ◽  
Distribution Functions ◽  
Inclusive Production ◽  
Leading Order ◽  
Parton Distribution Functions ◽  
Proton Proton ◽  
Proton Collisions ◽  
Intrinsic Charm ◽  
Proton Proton Collisions

We present predictions for the inclusive production of charm jets in proton–proton collisions at 7 TeV. Several CTEQ parton distribution functions (PDFs) of the CTEQ6.6M type are employed, where two of the CTEQ6.6 PDFs have intrinsic charm. At large enough jet transverse momentum and large jet rapidity, the intrinsic charm content can be tested.

scholarly journals Study of the Polarized Gluon Structure of a Proton via Prompt-Photon Production in the SPD Experiment at the NICA Collider

2019 ◽  
Vol 64 (7) ◽  
pp. 631 ◽  
Author(s):  
A. Rymbekova
Keyword(s):  
Parton Distribution ◽  
Distribution Functions ◽  
Prompt Photon ◽  
Hard Scattering ◽  
Parton Distribution Functions ◽  
Proton Proton ◽  
Proton Collisions ◽  
Polarized Proton ◽  
Proton Proton Collisions ◽  
Nica Collider

Photons produced in the hard scattering of partons, named prompt photons, provide information about the internal structure of hadrons. The NICA collider has the possibility to provide new data to study the production of prompt photons in non-polarized and polarized proton-proton collisions, which gives an access to spin-dependent parton distribution functions for gluons. Unpolarized and polarized physics with prompt photons and capabilities of the SPD detector in such measurements is discussed.

scholarly journals PION AND KAON PRODUCTION IN NUCLEON–NUCLEON COLLISIONS

2007 ◽  
Vol 22 (02n03) ◽  
pp. 582-586
Author(s):  
MARTA TICHORUK ◽  
ANTONI SZCZUREK
Keyword(s):  
Degrees Of Freedom ◽  
Inclusive Cross Section ◽  
Nucleon Nucleon ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Kaon Production ◽  
Factorization Approach ◽  
Proton Proton ◽  
Proton Collisions ◽  
Proton Proton Collisions

Inclusive cross section for pion production in proton - proton collisions are calculated based on unintegrated parton distribution functions (uPDFs). In addition to purely gluonic terms the present approach includes also quark degrees of freedom. Phenomenological fragmentation functions from the literature are used. The new mechanisms are responsible for π+ - π- asymmetry. In contrast to standard collinear approach, application of 2 → 1 kt - factorization approach can be extended towards much lower transverse momenta, both at mid and forward rapidity region. The results of the calculation are compared with SPS and RHIC data.

scholarly journals HIGGS PRODUCTION IN ASSOCIATION WITH BOTTOM QUARKS AT HADRON COLLIDERS

2006 ◽  
Vol 21 (02) ◽  
pp. 89-109 ◽  
Author(s):  
S. DAWSON ◽  
C. B. JACKSON ◽  
L. REINA ◽  
D. WACKEROTH
Keyword(s):  
Standard Model ◽  
Cross Sections ◽  
Hadron Collider ◽  
Distribution Functions ◽  
Bottom Quarks ◽  
Final States ◽  
Leading Order ◽  
Hadron Colliders ◽  
Parton Distribution Functions ◽  
Model Case

We review the present status of the QCD corrected cross-sections and kinematic distributions for the production of a Higgs boson in association with bottom quarks at the Fermilab Tevatron and CERN Large Hadron Collider. Results are presented for the Minimal Supersymmetric Standard Model where, for large tan β, these production modes can be greatly enhanced compared to the Standard Model case. The next-to-leading order QCD results are much less sensitive to the renormalization and factorization scales than the lowest order results, but have a significant dependence on the choice of the renormalization scheme for the bottom quark Yukawa coupling. We also investigate the uncertainties coming from the Parton Distribution Functions and find that these uncertainties can be comparable to the uncertainties from the remaining scale dependence of the next-to-leading order results. We present results separately for the different final states depending on the number of bottom quarks identified.

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