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 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 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 THE MESON PRODUCTION IN PROTON–PROTON COLLISIONS IN NEXT-TO-LEADING ORDER AND INFRARED RENORMALONS

2011 ◽  
Vol 20 (05) ◽  
pp. 1243-1270 ◽  
Author(s):  
A. I. AHMADOV ◽  
R. M. BURJALIYEV
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Production Cross ◽  
Meson Production ◽  
Leading Order ◽  
Proton Proton ◽  
Proton Collisions ◽  
Running Coupling ◽  
Coupling Approach ◽  
Proton Proton Collisions

In this paper, we investigate the next-to-leading order contribution of the higher-twist Feynman diagrams to the large-pT inclusive pion production cross-section in proton–proton collisions and present the general formulae for the higher-twist differential cross-sections in the case of the running coupling and frozen coupling approaches. We compared the resummed next-to-leading order higher-twist cross-sections with the ones obtained in the framework of the frozen coupling approach and leading-twist cross-section. The structure of infrared renormalon singularities of the higher-twist subprocess cross-section and its resummed expression (the Borel sum) are found. It is shown that the resummed result depends on the choice of the meson wave functions used in the calculations. We discuss the phenomenological consequences of possible higher-twist contributions to the meson production in proton–proton collisions in next-to-leading order at RHIC.

scholarly journals First measurement of the cross section for top-quark pair production in proton–proton collisions at s=7 TeV

2011 ◽  
Vol 695 (5) ◽  
pp. 424-443 ◽  
Author(s):  
V. Khachatryan ◽  
A.M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Pair Production ◽  
Cross Section ◽  
Top Quark ◽  
Proton Proton ◽  
Proton Collisions ◽  
The Cross ◽  
Proton Proton Collisions

scholarly journals HIGHER TWIST EFFECTS IN PROTON-PROTON COLLISIONS

2006 ◽  
Vol 15 (06) ◽  
pp. 1209-1231 ◽  
Author(s):  
A. I. AHMADOV ◽  
I. BOZTOSUN ◽  
R. KH. MURADOV ◽  
A. SOYLU ◽  
E. A. DADASHOV
Keyword(s):  
Wave Function ◽  
Cross Section ◽  
Cross Sections ◽  
Production Cross ◽  
Wave Functions ◽  
High Twist ◽  
Proton Proton ◽  
Proton Collisions ◽  
Pion Wave Function ◽  
Proton Proton Collisions

In this article, we investigate the contribution of the high twist Feynman diagrams to the large-pT pion production cross section in proton-proton collisions and we present the general formulae for the high and leading twist differential cross sections. The pion wave function where two non-trivial Gegenbauer coefficients a2 and a4 have been extracted from the CLEO data, two other pion model wave functions, P2, P3, the asymptotic and the Chernyak-Zhitnitsky wave functions are used in the calculations. The results of all the calculations reveal that the high twist cross sections, the ratios R, r, the dependence transverse momentum pT and the rapidity y of pion in the Φ CLEO (x,Q2) wave function case is very close to the Φ asy (x) asymptotic wave function case. It is shown that the high twist contribution to the cross section depends on the choice of the meson wave functions.

scholarly journals EXCITED HYPERONS PRODUCED IN PROTON-PROTON COLLISIONS WITH ANKE AT COSY

2009 ◽  
Vol 18 (02) ◽  
pp. 241-247 ◽  
Author(s):  
IZABELLA ZYCHOR
Keyword(s):  
Cross Section ◽  
Beam Momentum ◽  
Exotic State ◽  
Simultaneous Observation ◽  
Proton Proton ◽  
Proton Collisions ◽  
Decay Modes ◽  
The Cross ◽  
Hyperon Resonance ◽  
Proton Proton Collisions

Excited neutral hyperons Y0* produced in the pp → pK+Y0* reaction with a COSY beam momentum of 3.65 MeV/c have masses below 1540 MeV/c2. The ANKE spectrometer allows the simultaneous observation of different decay modes: Y0* → π0Σ0, π∓Σ±, π0Λ, K-p by measuring kaons and pions of either charge in coincidence with protons. We have found indications for a neutral excited hyperon resonance Y0* with a mass of M(Y0*) = (1480 ± 15) MeV / c 2 and a width of Γ(Y0*) = (60±15) MeV / c 2. The cross section for Y0* is of the order of few hundred nanobarns. It can be either a Σ0 or a Λ hyperon and on the basis of existing data no conclusion could be made whether it is a three–quark baryon or an exotic state. Missing- and invariant–mass techniques have been used to identify the Λ(1405) resonance decaying via Σ0π0. The cross section for Λ(1405) production is equal to (4.5 ± 0.9 stat ± 1.8 syst ) µb. The shape and position of the Λ(1405) distribution are similar to those found from other decay modes, so no support is given to the two-pole model.

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