scholarly journals Impact of scale, nuclear PDF and temperature variations on the interpretation of medium-modified jet production data from the LHC

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
A. Andronic ◽  
J. Honermann ◽  
M. Klasen ◽  
C. Klein-Bösing ◽  
J. Salomon
Keyword(s):  
Distribution Functions ◽  
Production Data ◽  
Crossover Temperature ◽  
Parton Distribution Functions ◽  
Temperature Variations ◽  
Nuclear Modification Factor ◽  
Nuclear Modification ◽  
Modification Factor ◽  
The Impact ◽  
Jet Structure

Abstract In this paper we present a study of in-medium jet modifications performed with JEWEL and PYTHIA 6.4, focusing on the uncertainties related to variations of the perturbative scales and nuclear parton distribution functions (PDFs) and on the impact of the initial and crossover temperature variations of the medium. The simulations are compared to LHC data for the jet spectrum and the nuclear modification factor. We assess the interplay between the choice of nuclear PDFs and different medium parameters and study the impact of nuclear PDFs and the medium on the jet structure via the Lund plane.

scholarly journals Jet radiation in a longitudinally expanding medium

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
P. Caucal ◽  
E. Iancu ◽  
G. Soyez
Keyword(s):  
Transverse Momentum ◽  
Gluon Plasma ◽  
Distribution Functions ◽  
Static Case ◽  
Parton Distribution Functions ◽  
New Approach ◽  
Nuclear Modification Factor ◽  
Modification Factor ◽  
Fragmentation Functions ◽  
Monte Carlo Implementation

Abstract In a series of previous papers, we have presented a new approach, based on perturbative QCD, for the evolution of a jet in a dense quark-gluon plasma. In the original formulation, the plasma was assumed to be homogeneous and static. In this work, we extend our description and its Monte Carlo implementation to a plasma obeying Bjorken longitudinal expansion. Our key observation is that the factorisation between vacuum-like and medium-induced emissions, derived in the static case, still holds for an expanding medium, albeit with modified rates for medium-induced emissions and transverse momentum broadening, and with a modified phase-space for vacuum-like emissions. We highlight a scaling relation valid for the energy spectrum of medium-induced emissions, through which the case of an expanding medium is mapped onto an effective static medium. We find that scaling violations due to vacuum-like emissions and transverse momentum broadening are numerically small. Our new predictions for the nuclear modification factor for jets RAA, the in-medium fragmentation functions, and substructure distributions are very similar to our previous estimates for a static medium, maintaining the overall good qualitative agreement with existing LHC measurements. In the case of RAA, we find that the agreement with the data is significantly improved at large transverse momenta pT ≳ 500 GeV after including the effects of the nuclear parton distribution functions.

scholarly journals Delineating the Polarized and Unpolarized Parton Structure of the Nucleon

2015 ◽  
Vol 37 ◽  
pp. 1560053
Author(s):  
Pedro Jimenez-Delgado
Keyword(s):  
Parton Distribution ◽  
Distribution Functions ◽  
Distribution Analysis ◽  
Coupling Constant ◽  
Parton Distribution Functions ◽  
Careful Treatment ◽  
Future Data ◽  
The Impact

Reports on our latest extractions of parton distribution functions of the nucleon are given. First an overview of the recent JR14 upgrade of our unpolarized PDFs, including NNLO determinations of the strong coupling constant and a discussion of the role of the input scale in parton distribution analysis. In the second part of the talk recent results on the determination of spin-dependent PDFs from the JAM collaboration are reported, including a careful treatment of hadronic and nuclear corrections, as well as reports on the impact of present and future data in our understanding of the spin of the nucleon.

scholarly journals ON THE $\bar{d}/\bar{u}$ ASYMMETRY AND PARTON DISTRIBUTIONS

2002 ◽  
Vol 17 (02) ◽  
pp. 269-278
Author(s):  
ALEJANDRO DALEO ◽  
CARLOS A. GARCIA CANAL ◽  
GABRIELA A. NAVARRO ◽  
RODOLFO SASSOT
Keyword(s):  
Parton Distribution ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Parton Distributions ◽  
The Impact

We discuss the impact of different measurements of the [Formula: see text] asymmetry in the extraction of parametrizations of parton distribution functions.

CENTRALITY DEPENDENCE OF NUCLEAR MODIFICATION FACTOR IN Au+Au COLLISIONS AT $\sqrt{s_{NN}}=200~{\rm GeV}$

2007 ◽  
Vol 22 (19) ◽  
pp. 1381-1389 ◽  
Author(s):  
W. C. XIANG ◽  
D. C. ZHOU
Keyword(s):  
Model Calculation ◽  
Centrality Dependence ◽  
Nuclear Modification Factor ◽  
Surface Emission ◽  
Nuclear Modification ◽  
Boltzmann Function ◽  
Modification Factor ◽  
Phenix Data

Centrality dependence of nuclear modification factor at high pT above 4 GeV /c is studied in nucleus–nucleus collisions at [Formula: see text]. We find that the centrality dependence of the nuclear modification factor can be factorized as a Boltzmann function F(b). Comparing our model calculation with PHENIX data, we further confirm that the high pT spectrum of particles is dominated by surface emission.

scholarly journals Chiral perturbation theory and nucleon–pion-state contaminations in lattice QCD

2017 ◽  
Vol 32 (15) ◽  
pp. 1730011 ◽  
Author(s):  
Oliver Bär
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Distribution Functions ◽  
Leading Order ◽  
Chiral Perturbation ◽  
Parton Distribution Functions ◽  
Physical Point ◽  
Source Sink ◽  
The Impact ◽  
Quark Momentum

Multiparticle states with additional pions are expected to be a non-negligible source of excited-state contamination in lattice simulations at the physical point. It is shown that baryon chiral perturbation theory can be employed to calculate the contamination due to two-particle nucleon–pion-states in various nucleon observables. Leading order results are presented for the nucleon axial, tensor and scalar charge and three Mellin moments of parton distribution functions (quark momentum fraction, helicity and transversity moment). Taking into account phenomenological results for the charges and moments the impact of the nucleon–pion-states on lattice estimates for these observables can be estimated. The nucleon–pion-state contribution results in an overestimation of all charges and moments obtained with the plateau method. The overestimation is at the 5–10% level for source-sink separations of about 2 fm. The source-sink separations accessible in contemporary lattice simulations are found to be too small for chiral perturbation theory to be directly applicable.

Sign in / Sign up

Export Citation Format

Share Document