scholarly journals Constraints on parton distributions and the strong coupling from LHC jet data

2015 ◽  
Vol 30 (31) ◽  
pp. 1546005 ◽  
Author(s):  
Juan Rojo
Keyword(s):  
Strong Coupling ◽  
State Of The Art ◽  
Distribution Functions ◽  
Coupling Constant ◽  
Hadron Colliders ◽  
Parton Distribution Functions ◽  
Jet Production ◽  
Future Developments ◽  
The Impact ◽  
First Time

Jet production at hadron colliders provides powerful constraints on the parton distribution functions (PDFs) of the proton, in particular on the gluon PDF. Jet production can also be used to extract the QCD coupling [Formula: see text] and to test its running with the momentum transfer up to the TeV region. In this review, I summarize the information on PDFs and the strong coupling that has been provided by Run I LHC jet data. First of all, I discuss why jet production is directly sensitive to the gluon and quark PDFs at large-x, and then review the state-of-the-art perturbative calculations for jet production at hadron colliders and the corresponding fast calculations required for PDF fitting. Then I present the results of various recent studies on the impact on PDFs, in particular the gluon, that have been performed using as input jet measurements from ATLAS and CMS. I also review the available determinations of the strong coupling constant based on ATLAS and CMS jet data, with emphasis on the fact that LHC jet data provides, for the first time, a direct test of the [Formula: see text] running at the TeV scale. I conclude with a brief outlook on possible future developments.

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 THE QCD COUPLING AND PARTON DISTRIBUTIONS AT HIGH PRECISION

2010 ◽  
Vol 25 (31) ◽  
pp. 2621-2636 ◽  
Author(s):  
JOHANNES BLÜMLEIN
Keyword(s):  
Strong Coupling ◽  
High Precision ◽  
Present Status ◽  
Strong Coupling Constant ◽  
Precision Measurements ◽  
Coupling Constant ◽  
Hadron Colliders ◽  
Parton Distributions ◽  
Precision Observables ◽  
The Impact

A survey is given on the present status of the nucleon parton distributions and related precision calculations and precision measurements of the strong coupling constant [Formula: see text]. We also discuss the impact of these quantities on precision observables at hadron colliders.

The impact of CMS inclusive jet data on parton distribution functions and their uncertainties

2017 ◽  
Vol 32 (22) ◽  
pp. 1750134
Author(s):  
A. Aleedaneshvar ◽  
A. Khorramian
Keyword(s):  
Parton Distribution ◽  
Parton Distribution Function ◽  
Global Analysis ◽  
Center Of Mass ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Jet Production ◽  
Inclusive Jet ◽  
Inclusive Jet Production ◽  
The Impact

It is well known that the jet production data at LHC provide important constraints on the medium and large-[Formula: see text] gluon parton distribution function (PDF), as well as on the large-[Formula: see text] sea quarks. In this work, we study the impact of recent CMS measurements for the inclusive jet production at center-of-mass energy of [Formula: see text][Formula: see text]=[Formula: see text]13 TeV on the PDFs and their uncertainties. To this aim, with use of the FastNLO and xFitter framework, we apply the parton distribution re-weighting procedure to study the impact of CMS data on two NLO modern CT14 and MMHT PDF sets. As a result, we found that the fit quality obtained using both of these PDF sets is very good. Moreover, the CMS data can impact both the central values and uncertainties of some PDFs especially at low and large [Formula: see text] regions. Overall, it is indicated that the CT14 PDFs compared with the MMHT ones are more affected. We emphasis that the inclusion of these data in a new global analysis of PDFs can improve the determination of the gluon and quark PDFs at both low and large [Formula: see text] regions.

Trace of nonperturbative charm content of the nucleon on Z + c-jet production

2017 ◽  
Vol 32 (16) ◽  
pp. 1750095
Author(s):  
S. Rostami ◽  
A. Khorramian
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Center Of Mass ◽  
Distribution Functions ◽  
Mass Energy ◽  
Parton Distribution Functions ◽  
Jet Production ◽  
Center Of Mass Energy ◽  
Intrinsic Charm ◽  
The Impact

We perform a comparison of the impact of different intrinsic charm (IC) models, based on the prediction of the differential cross-sections of [Formula: see text]-boson and [Formula: see text]-jet production in [Formula: see text] collision. It is shown that regardless of choosing the model, considering nonperturbative intrinsic charm component increases the magnitude of the cross-section when the [Formula: see text] transverse momentum grows or at large rapidity [Formula: see text] of the [Formula: see text]. Moreover, to evaluate the effect of different parton distribution functions (PDFs), we also compare the results of two PDF sets in prediction of production [Formula: see text]-jet in [Formula: see text] at a center-of-mass energy of 13 TeV with taking into account the intrinsic charm contribution in the proton. It is shown that the various PDF sets give some difference in the description of the [Formula: see text]-jet cross-section.

scholarly journals Erratum to: Determination of the strong coupling constant $${{\varvec{\alpha _{\mathrm{s}} (m_{\mathrm{Z}})}}}$$ in next-to-next-to-leading order QCD using H1 jet cross section measurements

2021 ◽  
Vol 81 (8) ◽  
Author(s):  
◽  
V. Andreev ◽  
A. Baghdasaryan ◽  
K. Begzsuren ◽  
A. Belousov ◽  
...  
Keyword(s):  
Strong Coupling ◽  
Cross Section ◽  
Distribution Functions ◽  
Strong Coupling Constant ◽  
Leading Order ◽  
Coupling Constant ◽  
Parton Distribution Functions ◽  
Section Data ◽  
Dijet Data

AbstractThe determination of the strong coupling constant $$\alpha _{\mathrm{s}} (m_{\mathrm{Z}})$$ α s ( m Z ) from H1 inclusive and dijet cross section data [1] exploits perturbative QCD predictions in next-to-next-to-leading order (NNLO) [2–4]. An implementation error in the NNLO predictions was found [4] which changes the numerical values of the predictions and the resulting values of the fits. Using the corrected NNLO predictions together with inclusive jet and dijet data, the strong coupling constant is determined to be $$\alpha _{\mathrm{s}} (m_{\mathrm{Z}}) =0.1166\,(19)_{\mathrm{exp}}\,(24)_{\mathrm{th}}$$ α s ( m Z ) = 0.1166 ( 19 ) exp ( 24 ) th . Complementarily, $$\alpha _{\mathrm{s}} (m_{\mathrm{Z}})$$ α s ( m Z ) is determined together with parton distribution functions of the proton (PDFs) from jet and inclusive DIS data measured by the H1 experiment. The value $$\alpha _{\mathrm{s}} (m_{\mathrm{Z}}) =0.1147\,(25)_{\mathrm{tot}}$$ α s ( m Z ) = 0.1147 ( 25 ) tot obtained is consistent with the determination from jet data alone. Corrected figures and numerical results are provided and the discussion is adapted accordingly.

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 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.

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