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We present an extraction of the unpolarized transverse-momentum-dependent parton distribution and fragmentation functions that takes into account possible differences between quark flavors and final-state hadrons. The extraction is based on…

The scale dependence of the ratios of parton distributions in a proton of a nucleus $A$ and in the free proton, $R_i^A(x,Q^2)=f_{i/A}(x,Q^2)/f_i(x,Q^2)$, is studied within the framework of the lowest order leading-twist DGLAP evolution. By…

High Energy Physics - Phenomenology · Physics 2014-11-17 K. J. Eskola , V. J. Kolhinen , C. A. Salgado

We show that when Bjorken $x_B$ is large, the leading order twist-four contributions to the structure functions can be expressed in terms of the derivatives of the normal twist-two parton distributions. Our analytical results are not only…

High Energy Physics - Phenomenology · Physics 2007-05-23 Xiaofeng Guo , Jianwei Qiu

A discussion is presented of the manner in which uncertainties in parton distributions and related quantities are determined. One of the central problems is the criteria used to judge what variation of the parameters describing a set of…

High Energy Physics - Phenomenology · Physics 2008-11-26 R. S. Thorne , H. Boettcher , A. M. Cooper-Sarkar , B. Reisert , V. Shekelyan , W. J. Stirling , D. R. Stump , A. Vogt

We present the matching relations of the variable flavor number scheme at next-to-leading order, which are of importance to define heavy quark partonic distributions for the use at high energy colliders such as Tevatron and the LHC. The…

High Energy Physics - Phenomenology · Physics 2018-07-04 J. Blümlein , A. De Freitas , C. Schneider , K. Schönwald

The idea of ``dynamically'' generated parton distribution functions, based on regular initial conditions at low momentum scale, is reanalyzed with particular emphasize paid to its compatibility with the factorization mechanism. Basic…

High Energy Physics - Phenomenology · Physics 2009-10-28 Jiri Chyla

In analogy with parton distribution functions, also parton fragmentation functions obey matching conditions when crossing heavy-flavour thresholds. We compute these matching conditions at next-to-leading order in the strong coupling…

High Energy Physics - Phenomenology · Physics 2010-02-03 Matteo Cacciari , Paolo Nason , Carlo Oleari

Understanding flavor dependence of the parton energy loss is one of key tasks of the jet quenching physics. In these proceedings we provide a summary of recent works on a quantification of the flavor dependence of parton energy loss along…

High Energy Physics - Phenomenology · Physics 2017-02-08 Martin Spousta

We have used QCD and polarized deep-inelastic scattering data to construct x-dependent polarized parton distributions. These flavor dependent distributions evolve under the NLO DGLAP equations, satisfy positivity constraints and agree well…

High Energy Physics - Phenomenology · Physics 2007-05-23 Gordon P. Ramsey

There are many mixing schemes based upon flavor symmetries that predict a vanishing $\theta_{13}$. These mixing schemes need corrections or modifications to account for recent experimental measurements of non-zero $\theta_{13}$. We propose…

High Energy Physics - Phenomenology · Physics 2013-08-02 Sanjeev Kumar

A study is made of charm and bottom flavor matching conditions on parton densities. Starting from an $\bar{\rm MS}$ three-flavor density set, where the scale $\mu < m_c$, and using the recently derived two-loop matching conditions, we…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. Chuvakin , J. Smith

In the framework of renormalon consideration, a role of the anomalous dependence of gluon propagator on the scale $\mu$ is shown for a large number of quark flavours as well as in the nonabelian theory, where the parameter of the "running"…

High Energy Physics - Phenomenology · Physics 2007-05-23 V. V. Kiselev

The $t$-dependence of generalized parton distrbutions for $x\to 1$ is discussed. We argue that constituent quark models, where the $t$-dependence for $x\to 1$ is through the product $(1-x)t$, are inconsistent. Instead we suggest a leading…

High Energy Physics - Phenomenology · Physics 2009-11-10 Matthias Burkardt

The soft production problem in hadronic collisions as described in the eikonal color mutation branching model is improved in the way that the initial parton distribution is treated. Furry branching of the partons is considered as a means of…

High Energy Physics - Phenomenology · Physics 2009-10-31 R. C. Hwa , Y. Wu

The separate quark flavour contributions to the pion and kaon valence quark distribution functions are studied, along with the corresponding electromagnetic form factors in the space-like region. The calculations are made using the solution…

Nuclear Theory · Physics 2016-09-07 Parada T. P. Hutauruk , Ian C. Cloet , Anthony W. Thomas

It is usually assumed that the high-energy evolution of partons in QCD remains local in coordinate space. In particular, fixed impact-parameter scattering is thought to be in the universality class of one-dimensional reaction-diffusion…

High Energy Physics - Phenomenology · Physics 2009-01-09 S. Munier , G. P. Salam , G. Soyez

In these lectures the three flavor soliton approach for baryons is reviewed. Effects of flavor symmetry breaking in the baryon wave--functions on axial current matrix elements are discussed. A bosonized chiral quark model is considered to…

High Energy Physics - Phenomenology · Physics 2009-11-07 Herbert Weigel

A flavor-dependent model (FDM) is proposed in this work. The model extends the Standard Model by an extra $U(1)_F$ local gauge group, two scalar doublets, one scalar singlet and two right-handed neutrinos, where the additional $U(1)_F$…

High Energy Physics - Phenomenology · Physics 2024-05-29 Jin-Lei Yang , Hai-Bin Zhang , Tai-Fu Feng

Supposing only that there is an effective charge which defines an evolution scheme for parton distribution functions (DFs) that is all-orders exact, strict lower and upper bounds on all Mellin moments of the valence-quark DFs of pion-like…

High Energy Physics - Phenomenology · Physics 2022-06-01 Z. -F. Cui , M. Ding , J. M. Morgado , K. Raya , D. Binosi , L. Chang , F. De Soto , C. D. Roberts , J. Rodríguez-Quintero , S. M. Schmidt

We introduce a Hybrid Variable Flavor Number Scheme (H-VFNS) for heavy flavors, which incorporates the advantages of both the traditional Variable Flavor Number Scheme (VFNS) as well as the Fixed Flavor Number Scheme (FFNS). We include an…

High Energy Physics - Phenomenology · Physics 2013-12-13 A. Kusina , F. I. Olness , I. Schienbein , T. Jezo , K. Kovarik , T. Stavreva , J. Y. Yu