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Quantum Chromodynamics with a relatively large number of fundamentally charged quark flavours in the chiral limit is considered. A self-consistent solution of the quark, gluon and ghost propagator Dyson-Schwinger equations in Landau gauge…

High Energy Physics - Phenomenology · Physics 2015-06-19 Markus Hopfer , Christian S. Fischer , Reinhard Alkofer

We present a test of the flavour independence of the strong coupling constant for charm and bottom quarks with respect to light (uds) quarks, based on a hadronic event sample obtained with the OPAL detector at LEP. Five observables related…

High Energy Physics - Experiment · Physics 2008-11-26 The OPAL Collaboration , G. Abbiendi et al

In the high energy regime, the proton structure consists of a very large number of particles called partons (quarks and gluons) that interact with each other, according to the theory of strong interactions, Quantum Chromodynamics (QCD).…

High Energy Physics - Phenomenology · Physics 2018-08-06 Gilvana C. Penedo , Werner K. Sauter

By considering clans as genuine elementary subprocesses, i.e., intermediate parton sources in the Simplified Parton Shower model, a generalized version of this model is defined. It predicts analytically clan properties at parton level in…

High Energy Physics - Phenomenology · Physics 2009-09-25 R. Ugoccioni , A. Giovannini , S. Lupia

We use lattice regularization to study the flow of the flavor-triplet fermion current central charge $C^f_J$ from its free field value in the ultraviolet limit to its conformal value in the infrared limit of the parity-invariant…

High Energy Physics - Theory · Physics 2017-09-20 Nikhil Karthik , Rajamani Narayanan

Flavor transitions via the charged current interactions are parametrized by a three dimensional and unitary transformation. This so called mixing matrix requires of four mixing parameters. Here we show that under the phenomenological…

High Energy Physics - Phenomenology · Physics 2016-11-23 U. J. Saldaña-Salazar

A grand unified $SU(5)$ theory is constructed with a hierarchical breaking of a $U(2)$ flavor symmetry. The small parameters of the squark and slepton mass matrices, necessary to solve the supersymmetric flavor-changing problem, and the…

High Energy Physics - Phenomenology · Physics 2007-05-23 Riccardo Barbieri , Lawrence Hall

We study the flavor-changing quark-graviton vertex that is induced at the one-loop level when gravitational interactions are coupled to the standard model. Because of the conservation of the energy-momentum tensor the corresponding form…

High Energy Physics - Phenomenology · Physics 2009-03-24 G. Degrassi , E. Gabrielli , L. Trentadue

The flavor-dependent valence, sea quark and antiquark spin distributions can be determined separately from theoretical assumptions and experimental data. We have determined the valence distributions using the Bjorken sum rule and have…

High Energy Physics - Phenomenology · Physics 2014-11-17 Gordon P. Ramsey

Nuclear parton distributions and structure functions are determined in an effective chiral quark theory. We also discuss an extension of our model to fragmentation functions.

Nuclear Theory · Physics 2009-03-27 W. Bentz , I. C. Cloët , T. Ito , A. W. Thomas , K. Yazaki

Our interest is in the scaled joint distribution associated with $k$-increasing subsequences for random involutions with a prescribed number of fixed points. We proceed by specifying in terms of correlation functions the same distribution…

Combinatorics · Mathematics 2007-05-23 Peter J. Forrester , Taro Nagao , Eric M. Rains

We have calculated the step scaling function and the running coupling of QCD in the Schroedinger functional scheme with four flavors of O(a) improved Wilson quarks. Comparisons of our non-perturbative results with 2-loop and 3-loop…

High Energy Physics - Lattice · Physics 2014-11-21 Fatih Tekin , Rainer Sommer , Ulli Wolff

In a model proposed in 2012, all flavor mixing has a single source and is governed by a single "master matrix." This model was shown to give several predictions for quark and lepton masses and mixing angles and for mixing angles within…

High Energy Physics - Phenomenology · Physics 2015-06-02 Stephen M. Barr , Heng-Yu Chen

Modular transformations of string theory are shown to play a crucial role in the discussion of discrete flavor symmetries in the Standard Model. They include CP transformations and provide a unification of CP with traditional flavor…

High Energy Physics - Theory · Physics 2021-05-14 Hans Peter Nilles , Saul Ramos-Sanchez , Patrick K. S. Vaudrevange

We compute all kaon and pion parton distribution amplitudes (PDAs) to twist-three and find that only the pseudotensor PDA can reasonably be approximated by its conformal limit expression. At terrestrially accessible energy scales, the…

Nuclear Theory · Physics 2015-04-06 Chao Shi , Chen Chen , Lei Chang , Craig D. Roberts , Sebastian M. Schmidt , Hong-Shi Zong

Since the x dependence of the axial-anomaly effect in inclusive polarized deep inelastic scattering is fixed, the transformation from the $\bar{MS}$ scheme to different factorization schemes are not arbitrary. If the quark spin distribution…

High Energy Physics - Phenomenology · Physics 2009-10-30 Hai-Yang Cheng

The non-local dependence of the fermion determinant on the gauge field limits our ability of simulating Quantum Chromodynamics on the lattice. Here we present a factorization of the gauge field dependence of the fermion determinant based on…

High Energy Physics - Lattice · Physics 2022-11-15 Matteo Saccardi , Leonardo Giusti

Taking proton as an ensemble of quark-gluon Fock states and using the principle of detailed balance, we construct a simple statistical model for parton distribution of proton. The recent observed Bjorken-$x$ dependent light flavor sea quark…

High Energy Physics - Phenomenology · Physics 2009-11-07 Yong-Jun Zhang , Bing-Song Zou , Li-Ming Yang

Evolution of a multiplicity distribution can be described with the help of master equation. We first look at 3rd and 4th factorial moments of multiplicity distributions and derive their equilibrium values. From them central moments and…

Nuclear Theory · Physics 2018-11-05 Radka Sochorova , Boris Tomasik

The approximate chiral invariance of the two-flavor QCD is known to be spontaneously broken. This effect explains the relatively small pion mass and, as is widely believed, the mass splittings of would-be chiral partners --- the hadrons of…

High Energy Physics - Phenomenology · Physics 2014-10-09 S. S. Afonin