scholarly journals Low-x improved TMD approach to the lepto- and hadroproduction of a heavy-quark pair

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Tolga Altinoluk ◽  
Cyrille Marquet ◽  
Pieter Taels
Keyword(s):  
Transverse Momentum ◽  
Heavy Quark ◽  
Quark Mass ◽  
Photon Virtuality ◽  
Linearly Polarized ◽  
Heavy Quark Pair ◽  
Saturation Effects ◽  
Low X

Abstract We study the lepto- and hadroproduction of a heavy-quark pair in the ITMD factorization framework for dilute-dense collisions. Due to the presence of a nonzero quark mass and/or nonzero photon virtuality, new contributions appear compared to the cases of photo- and hadroproduction of dijets, for which the ITMD framework was originally derived. These extra terms are sensitive to gluons that are not fully linearly polarized. At small x, those gluons emerge only when all saturation effects are carefully taken into account. Therefore, the resulting contributions are absent in linear small-x frameworks, where gluons are fully linearly polarized. We show, however, that even for large gluon transverse momentum, these contributions are not always negligible, due to the behavior of the off-shell hard factors.

scholarly journals How to measure the linear polarization of gluons in unpolarized proton using the heavy-quark pair production

2019 ◽  
Vol 204 ◽  
pp. 02006 ◽  
Author(s):  
N. Ya. Ivanov ◽  
A. V. Efremov ◽  
O. V. Teryaev
Keyword(s):  
Pair Production ◽  
Heavy Quark ◽  
Linear Polarization ◽  
Heavy Quark Production ◽  
Production Plane ◽  
Linearly Polarized ◽  
Quark Production ◽  
Mulders Function ◽  
Heavy Quark Pair ◽  
Azimuthal Asymmetries

In recent papers [1, 2], two new ways have been proposed to probe the linear polarization of gluons in unpolarized proton: using the azimuthal asymmetries and Callan-Gross ratio in heavy-quark pair leptoproduction, lN → l′QQ̅X. In this talk, we discuss in details the sensitivity of the QCD predictions for the azimuthal cos φ and cos 2φ asymmetries to the contribution of linearly polarized gluons inside unpolarized proton, where the azimuth φ is the angle between the lepton scattering plane (l, l′) and the heavy quark production plane (N, Q). Our analysis shows that the azimuthal distributions under consideration vary from 0 to 1 depending on the value of the gluonic counterpart of the Boer- Mulders function, $h_{1}^{ \bot g}$. We conclude that the cos φ and cos 2φ asymmetries in heavy-quark pair production in DIS processes are predicted to be large in wide kinematic ranges and sensitive to the contribution of linearly polarized gluons.

scholarly journals Low transverse momentum heavy quark pair production to probe gluon tomography

2013 ◽  
Vol 727 (4-5) ◽  
pp. 474-479 ◽  
Author(s):  
Ruilin Zhu ◽  
Peng Sun ◽  
Feng Yuan
Keyword(s):  
Transverse Momentum ◽  
Pair Production ◽  
Heavy Quark ◽  
Heavy Quark Pair

scholarly journals TMD factorization for dijet and heavy-meson pair in DIS

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Rafael F. del Castillo ◽  
Miguel G. Echevarria ◽  
Yiannis Makris ◽  
Ignazio Scimemi
Keyword(s):  
Transverse Momentum ◽  
Heavy Quark ◽  
Anomalous Dimension ◽  
Heavy Meson ◽  
Effective Field ◽  
Transverse Momentum Dependent ◽  
Soft Function ◽  
Linearly Polarized ◽  
Momentum Imbalance ◽  
Meson Pair

Abstract We study a transverse momentum dependent (TMD) factorization framework for the processes of dijet and heavy-meson pair production in deep-inelastic-scattering in an electron-proton collider, considering the measurement of the transverse momentum imbalance of the two hard probes in the Breit frame. For the factorization theorem we employ soft-collinear and boosted-heavy-quark effective field theories. The factorized cross-section for both processes is sensitive to gluon unpolarized and linearly polarized TMD distributions and requires the introduction of a new soft function. We calculate the new soft function here at one-loop, regulating rapidity divergences with the δ-regulator. In addition, using a factorization consistency relation and a universality argument regarding the heavy-quark jet function, we obtain the anomalous dimension of the new soft function at two and three loops.

scholarly journals The A-Dependence of Open Charm and Bottom Production

2003 ◽  
Vol 12 (02) ◽  
pp. 211-269 ◽  
Author(s):  
R. Vogt
Keyword(s):  
Transverse Momentum ◽  
Pair Production ◽  
Heavy Quark ◽  
Open Charm ◽  
Fixed Target ◽  
Nuclear Dependence ◽  
Heavy Quark Pair ◽  
Nuclear Effects ◽  
Intrinsic Transverse Momentum

We study inclusive heavy quark and exclusive heavy quark pair production in pp and pA interactions. Intrinsic transverse momentum is introduced in pp interactions. Nuclear effects are introduced in pA interactions, including kT broadening and nuclear shadowing. The nuclear dependence is studied over a range of energies, both in fixed target and collider setups.

scholarly journals Heavy-flavor hadro-production with heavy-quark masses renormalized in the $$ \overline{\mathrm{MS}} $$, MSR and on-shell schemes

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
M. V. Garzelli ◽  
L. Kemmler ◽  
S. Moch ◽  
O. Zenaiev
Keyword(s):  
Heavy Quark ◽  
Cross Sections ◽  
Top Quark ◽  
Quark Mass ◽  
Production Cross ◽  
Hadron Collider ◽  
Distribution Functions ◽  
Heavy Flavor ◽  
Parton Distribution Functions ◽  
Heavy Quark Mass

Abstract We present predictions for heavy-quark production at the Large Hadron Collider making use of the $$ \overline{\mathrm{MS}} $$ MS ¯ and MSR renormalization schemes for the heavy-quark mass as alternatives to the widely used on-shell renormalization scheme. We compute single and double differential distributions including QCD corrections at next-to-leading order and investigate the renormalization and factorization scale dependence as well as the perturbative convergence in these mass renormalization schemes. The implementation is based on publicly available programs, MCFM and xFitter, extending their capabilities. Our results are applied to extract the top-quark mass using measurements of the total and differential $$ t\overline{t} $$ t t ¯ production cross-sections and to investigate constraints on parton distribution functions, especially on the gluon distribution at low x values, from available LHC data on heavy-flavor hadro-production.

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