Small x Physics at the SSC and the Tevatron

1987 ◽  
Vol 02 (04) ◽  
pp. 1413-1423 ◽  
Author(s):  
FREDRICK OLNESS ◽  
WU-KI TUNG
Keyword(s):  
Pair Production ◽  
Production Process ◽  
Cross Sections ◽  
Differential Cross ◽  
Parton Distribution ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Small X ◽  
B Quark ◽  
Pair Production Process

We examine the integrated rates and differential cross-sections for b-quark pair production and Drell-Yan processes at the SSC and the Tevatron colliders, and we determine their sensitivity to a range of possible small x behaviors for the parton distribution functions (PDF’s). We find that both the integrated rates and the differential distributions for the Drell-Yan process are very sensitive to the unknown small x behavior of the PDF’s; whereas, only the integrated rates can distinguish various input PDF’s in the b-pair production process. Experiments at the Tevatron can provide very useful information on small x physics if these two processes, especially Drell-Yan, can be measured.

PARTON DISTRIBUTION FUNCTIONS AND THE QCD-IMPROVED PARTON MODEL — AN OVERVIEW

1987 ◽  
Vol 02 (04) ◽  
pp. 1369-1387 ◽  
Author(s):  
Wu-Ki Tung
Keyword(s):  
Parton Distribution ◽  
Particle Production ◽  
Heavy Particle ◽  
Parton Model ◽  
Distribution Functions ◽  
Collider Physics ◽  
Parton Distribution Functions ◽  
Parton Distributions ◽  
First Order ◽  
Small X

Some non-trivial features of the QCD-improved parton model relevant to applications on heavy particle production and semi-hard (small-x) processes of interest to collider physics are reviewed. The underlying ideas are illustrated by a simple example. Limitations of the naive parton formula as well as first order corrections and subtractions to it are dis-cussed in a quantitative way. The behavior of parton distribution functions at small x and for heavy quarks are discussed. Recent work on possible impact of unconventional small-x behavior of the parton distributions on small-x physics at SSC and Tevatron are summarized. The Drell-Yan process is found to be particularly sensitive to the small x dependence of parton distributions. Measurements of this process at the Tevatron can provide powerful constraints on the expected rates of semi-hard processes at the SSC.

scholarly journals A MODEL CONSTRUCTION OF SELF-SIMILARITY BASED DOUBLE PARTON DISTRIBUTION FUNCTIONS FOR PROTON–PROTON COLLISION AT LHC

2013 ◽  
Vol 28 (17) ◽  
pp. 1350079 ◽  
Author(s):  
D. K. CHOUDHURY ◽  
AKBARI JAHAN
Keyword(s):  
Parton Distribution ◽  
Distribution Functions ◽  
Model Construction ◽  
Proton Collision ◽  
Self Similarity ◽  
Parton Distribution Functions ◽  
Proton Proton ◽  
Construction Of Self ◽  
Small X ◽  
Proton Proton Collision

We construct a model for double parton distribution functions (dPDFs) based on the notion of self-similarity, pursued earlier for small x physics at HERA. The most general form of dPDFs contains total 13 parameters to be fitted from data of proton–proton collision at LHC. It is shown that the constructed dPDF does not factorize into two single PDFs in conformity with QCD expectation, and it satisfies the condition that at the kinematic boundary x1+x2 = 1 (where x1 and x2 are the longitudinal fractional momenta of two partons), the dPDF vanishes.

scholarly journals Measurement of $$W^\pm $$ boson production in Pb+Pb collisions at $$\sqrt{s_{\mathrm{NN}}} = 5.02~\text {Te}\text {V}$$ with the ATLAS detector

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Cross Sections ◽  
Parton Distribution ◽  
Production Cross ◽  
Charge Asymmetry ◽  
Distribution Functions ◽  
Boson Production ◽  
Parton Distribution Functions ◽  
Absolute Value ◽  
The Absolute ◽  
Thickness Function

AbstractA measurement of $$W^\pm $$W± boson production in Pb+Pb collisions at $$\sqrt{s_\mathrm {NN}} = 5.02~\text {Te}\text {V}$$sNN=5.02Te is reported using data recorded by the ATLAS experiment at the LHC in 2015, corresponding to a total integrated luminosity of $$0.49\;\mathrm {nb^{-1}}$$0.49nb-1. The $$W^\pm $$W± bosons are reconstructed in the electron or muon leptonic decay channels. Production yields of leptonically decaying $$W^\pm $$W± bosons, normalised by the total number of minimum-bias events and the nuclear thickness function, are measured within a fiducial region defined by the detector acceptance and the main kinematic requirements. These normalised yields are measured separately for $$W^+$$W+ and $$W^-$$W- bosons, and are presented as a function of the absolute value of pseudorapidity of the charged lepton and of the collision centrality. The lepton charge asymmetry is also measured as a function of the absolute value of lepton pseudorapidity. In addition, nuclear modification factors are calculated using the $$W^\pm $$W± boson production cross-sections measured in pp collisions. The results are compared with predictions based on next-to-leading-order calculations with CT14 parton distribution functions as well as with predictions obtained with the EPPS16 and nCTEQ15 nuclear parton distribution functions. No dependence of normalised production yields on centrality and a good agreement with predictions are observed for mid-central and central collisions. For peripheral collisions, the data agree with predictions within 1.7 (0.9) standard deviations for $$W^-$$W- ($$W^+$$W+) bosons.

scholarly journals Asymmetry Effects in Polarized Hadron Scattering

1997 ◽  
Vol 12 (32) ◽  
pp. 5827-5846
Author(s):  
Yaw-Hwang Chen ◽  
Su-Long Nyeo ◽  
Chung-Yi Wu
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Helicity Amplitude ◽  
Spin Asymmetry ◽  
Distribution Functions ◽  
Differential Cross Sections ◽  
Parton Distribution Functions ◽  
Double Spin Asymmetry ◽  
Single Spin ◽  
Double Spin

We calculate the single-spin and double-spin asymmetry differential cross sections for the polarized hadron scattering PP → l+ l- + jet up to O(αs) by the helicity amplitude method. Numerical results of the differential cross sections, which can be used to probe the spin contents of the proton, are obtained from several sets of polarized parton distribution functions.

scholarly journals Hadron interactions for arbitrary energies and species, with applications to cosmic rays

2022 ◽  
Vol 82 (1) ◽  
Author(s):  
Torbjörn Sjöstrand ◽  
Marius Utheim
Keyword(s):  
Cosmic Rays ◽  
Nuclear Matter ◽  
Cross Sections ◽  
Parton Distribution ◽  
Distribution Functions ◽  
Simplified Model ◽  
Event Generator ◽  
Parton Distribution Functions ◽  
Wide Range ◽  
Detector Material

AbstractThe Pythia event generator is used in several contexts to study hadron and lepton interactions, notably $$\mathrm{p}\mathrm{p}$$ p p and $$\mathrm{p}{\bar{\mathrm{p}}}$$ p p ¯ collisions. In this article we extend the hadronic modelling to encompass the collision of a wide range of hadrons h with either a proton or a neutron, or with a simplified model of nuclear matter. To this end we model $$h\mathrm{p}$$ h p total and partial cross sections as a function of energy, and introduce new parton distribution functions for a wide range of hadrons, as required for a proper modelling of multiparton interactions. The potential usefulness of the framework is illustrated by a simple study of the evolution of cosmic rays in the atmosphere, and by an even simpler one of shower evolution in a solid detector material. The new code will be made available for future applications.

Sign in / Sign up

Export Citation Format

Share Document