scholarly journals Color-singlet contribution toe+e−→J/ψ+Xat the endpoint

2007 ◽  
Vol 76 (3) ◽  
Author(s):  
Adam K. Leibovich ◽  
Xiaohui Liu
Keyword(s):  
Color Singlet ◽  
Singlet Contribution

scholarly journals Collinear expansion for color singlet cross sections

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Markus A. Ebert ◽  
Bernhard Mistlberger ◽  
Gherardo Vita
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Production Cross ◽  
Gluon Fusion ◽  
Building Blocks ◽  
Color Singlet ◽  
Final State ◽  
Beam Function ◽  
Kinematic Limit ◽  
State Radiation

Abstract We demonstrate how to efficiently expand cross sections for color-singlet production at hadron colliders around the kinematic limit of all final state radiation being collinear to one of the incoming hadrons. This expansion is systematically improvable and applicable to a large class of physical observables. We demonstrate the viability of this technique by obtaining the first two terms in the collinear expansion of the rapidity distribution of the gluon fusion Higgs boson production cross section at next-to-next-to leading order (NNLO) in QCD perturbation theory. Furthermore, we illustrate how this technique is used to extract universal building blocks of scattering cross section like the N-jettiness and transverse momentum beam function at NNLO.

scholarly journals ηQ Meson Photoproduction in Ultrarelativistic Heavy Ion Collisions

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Gong-Ming Yu ◽  
Gao-Gao Zhao ◽  
Zhen Bai ◽  
Yan-Bing Cai ◽  
Hai-Tao Yang ◽  
...  
Keyword(s):  
Heavy Ion Collisions ◽  
Hadron Collider ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Heavy Quarkonium ◽  
Color Singlet ◽  
Initial State ◽  
Color Octet ◽  
Ion Collisions ◽  
The Matrix

The transverse momentum distributions for inclusive ηc,b meson described by gluon-gluon interactions from photoproduction processes in relativistic heavy ion collisions are calculated. We considered the color-singlet (CS) and color-octet (CO) components within the framework of Nonrelativistic Quantum Chromodynamics (NRQCD) in the production of heavy quarkonium. The phenomenological values of the matrix elements for the color-singlet and color-octet components give the main contribution to the production of heavy quarkonium from the gluon-gluon interaction caused by the emission of additional gluon in the initial state. The numerical results indicate that the contribution of photoproduction processes cannot be negligible for midrapidity in p-p and Pb-Pb collisions at the Large Hadron Collider (LHC) energies.

Charmonia production in W → (cc̄)Ds(∗) decays

2021 ◽  
Vol 36 (09) ◽  
pp. 2150058
Author(s):  
A. V. Luchinsky ◽  
A. K. Likhoded
Keyword(s):  
Quantum Chromodynamics ◽  
Light Cone ◽  
Relativistic Quantum ◽  
Branching Fractions ◽  
Color Singlet ◽  
Leading Order ◽  
Paper Production ◽  
Quantum Numbers ◽  
Numerical Predictions ◽  
State Formula

In this paper, production of charmonium state [Formula: see text] in exclusive [Formula: see text] decays is analyzed in the framework of both leading order Non-relativistic Quantum Chromodynamics (NRQCD) and light-cone (LC) expansion models. Analytical and numerical predictions for the branching fractions of these decays in both the approaches are given. The typical value of the branching fractions is [Formula: see text][Formula: see text][Formula: see text] and it turns out that the LC results are significantly larger than NRQCD ones (approximately two or four times increase depending on the quantum numbers of the final particles), so the effect of internal quark motion should be taken into account. Some rough estimates of color-octet contributions are presented and it is shown that these contributions could be comparable with color-singlet results.

scholarly journals NOVEL HARD SEMIEXCLUSIVE PROCESSES AND COLOR SINGLET CLUSTERS IN HADRONS

2002 ◽  
Author(s):  
LEONID FRANKFURT ◽  
M. V. POLYAKOV ◽  
M. STRIKMAN ◽  
D. ZHALOV ◽  
M. ZHALOV
Keyword(s):  
Color Singlet

scholarly journals QCD theory of the hadrons and filling the Yang-Mills mass gap

2020 ◽  
Author(s):  
Jay R. Yablon
Keyword(s):  
Magnetic Monopoles ◽  
Exclusion Principle ◽  
Color Singlet ◽  
Gauge Bosons ◽  
Yang Mills ◽  
Mass Gap ◽  
Net Flux ◽  
Strength Gradient ◽  
Electric Source ◽  
The Magnetic Field

The rank-3 antisymmetric tensors which are the magnetic monopoles of SU(N) Yang-Mills gauge theory dynamics, unlike their counterparts in Maxwell’s U(1) electrodynamics, are non-vanishing, and do permit a net flux of Yang-Mills analogs to the magnetic field through closed spatial surfaces. When electric source currents of the same Yang-Mills dynamics are inverted and their fermions inserted into these Yang-Mills monopoles to create a system, this system in its unperturbed state contains exactly 3 fermions due to the monopole rank-3 and its 3 additive field strength gradient terms in covariant form. So to ensure that every fermion in this system occupies an exclusive quantum state, the Exclusion Principle is used to place each of the 3 fermions into the fundamental representation of the simple gauge group with an SU(3) symmetry. After the symmetry of the monopole is broken to make this system indivisible, the gauge bosons inside the monopole become massless, the SU(3) color symmetry of the fermions becomes exact, and a propagator is established for each fermion. The monopoles then have the same antisymmetric color singlet wavefunction as a baryon, and the field quanta of the magnetic fields fluxing through the monopole surface have the same symmetric color singlet wavefunction as a meson. Consequently, we are able to identify these fermions with colored quarks, the gauge bosons with gluons, the magnetic monopoles with baryons, and the fluxing entities with mesons, while establishing that the quarks and gluons remain confined and identifying the symmetry breaking with hadronization. Analytic tools developed along the way are then used to fill the Yang-Mills mass gap.

scholarly journals Color singlet and adjoint free energy at finite temperature

2009 ◽  
Author(s):  
Alexei Bazavov ◽  
Peter Petreczky ◽  
Alexander Velytsky
Keyword(s):  
Free Energy ◽  
Finite Temperature ◽  
Color Singlet

scholarly journals Analysis of the DD¯⁎K System with QCD Sum Rules

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Zun-Yan Di ◽  
Zhi-Gang Wang
Keyword(s):  
Spectral Density ◽  
Sum Rules ◽  
Resonance State ◽  
Energy Scale ◽  
Color Singlet ◽  
Qcd Sum Rules ◽  
Optimal Energy ◽  
Numerical Result ◽  
The Future ◽  
Vacuum Condensates

In this article, we construct the color singlet-singlet-singlet interpolating current with IJP=3/21- to study the DD¯⁎K system through QCD sum rules approach. In calculations, we consider the contributions of the vacuum condensates up to dimension-16 and employ the formula μ=MX/Y/Z2-2Mc2 to choose the optimal energy scale of the QCD spectral density. The numerical result MZ=4.71-0.11+0.19 GeV indicates that there exists a resonance state Z lying above the DD¯⁎K threshold to saturate the QCD sum rules. This resonance state Z may be found by focusing on the channel J/ψπK of the decay B→J/ψππK in the future.

FERMION-SECTOR FRUSTRATED SU(4) AS A PREONIC PRECURSOR OF THE STANDARD MODEL

1999 ◽  
Vol 14 (12) ◽  
pp. 1911-1934 ◽  
Author(s):  
STEPHEN L. ADLER
Keyword(s):  
Weak Interactions ◽  
Group Analysis ◽  
Algebra Structure ◽  
Color Singlet ◽  
Composite Fermions ◽  
Renormalization Group Analysis ◽  
Gauge Algebra ◽  
Composite Higgs ◽  
Fermionic Sector ◽  
Doorway State

We give a model for composite quarks and leptons based on the semisimple gauge group SU(4), with the preons in the 10 representation; this choice of gauge gluon and preon multiplets is motivated by the possibility of embedding them in an N=6 supergravity multiplet, with the preons and antipreons both in the 20 of SU(6). Hypercolor singlets are forbidden in the fermionic sector of this theory; we propose that the SU(4) symmetry spontaneously breaks to SU (3)× U (1), with the binding of triality nonzero preons and gluons into composites, and with the formation of a color singlet condensate that breaks the initial Z12 vacuum symmetry to Z6. The spin ½ fermionic composites have the triality structure of a quark–lepton family, and the initial Z12 symmetry implies that there are six massless families, which mix to give three distinct families below the scale of the condensate. The spin 1 triality zero composites of the color triplet SU(4) gluons, when coupled to the condensate and with the color singlet representation of the 10 acting as a doorway state, lead to weak interactions of the fermionic composites through an SU(2) gauge algebra. The initial Z12 symmetry implies that this SU(2) gauge algebra structure is doubled, which in turn permits the corresponding independent gauge bosons to couple to chiral components of the composite fermions. Since the U(1) couples to the 10 representation as B-L, an effective SU (2)L× SU (2)R × U (1)B-L electroweak theory arises at the condensate scale, with all composites having the correct electric charge structure. Assuming a mechanism for forming composite Higgs bosons, the Z12→ Z6 symmetry breaking chain implies that below the condensate scale there can be two sets of discrete chiral Z6 triplets of Higgs doublets, as required by a phenomenological model for the CKM matrix that we have analyzed in detail elsewhere. A renormalization group analysis of the SU(4) model shows that the conversion by binding of one 10 of SU(4) to 12 triplets of SU(3) can give a very large, calculable hierarchy ratio between the SU(4) and the hadronic mass scales.

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