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38
نتائج ل
"Goldhaber, Alfred S"
صنف حسب:
QCD Hidden-Color Hexa-diquark in the Central Core of Nuclei
Hidden-color configurations are a key prediction of QCD with important physical consequences. In this work we examine a QCD color-singlet configuration in nuclei formed by combining six scalar \\([u d]\\) diquarks in a strongly bound \\(\\rm SU(3)_C\\) channel. The resulting hexadiquark state is a charge-2, spin-0, baryon number-4, isospin-0, color-singlet state. It contributes to alpha clustering in light nuclei and to the additional binding energy not saturated by ordinary nuclear forces in \\he as well as the alpha-nuclei sequence of interest for nuclear astrophysics. We show that the strongly bound combination of six scalar isospin-0 \\([ud]\\) diquarks within the nuclear wave function - relative to free nucleons - provides a natural explanation of the EMC effect measured by the CLAS collaboration's comparison of nuclear parton distribution function ratios for a large range of nuclei. These experiments confirmed that the EMC effect; i.e., the distortion of quark distributions within nuclei, is dominantly identified with the dynamics of neutron-proton (``isophobic'') short-range correlations within the nuclear wave function rather than proton-proton or neutron-neutron correlations.
Paper
The Ridge Effect, Azimuthal Correlations, and other Novel Features of Gluonic String Collisions in High Energy Photon-Mediated Reactions
One of the remarkable features of high-multiplicity hadronic events in proton-proton collisions at the LHC is the fact that the produced particles appear as two \"ridges\", opposite in azimuthal angle \\(\\phi\\), with approximately flat rapidity distributions. This phenomena can be identified with the inelastic collision of gluonic flux tubes associated with the QCD interactions responsible for quark confinement in hadrons. In this paper we analyze the ridge phenomena when the collision involves a flux tube connecting the quark and antiquark of a high energy real or virtual photon. We discuss gluonic tube string collisions in the context of two examples: electron-proton scattering at a future electron-ion collider or the peripheral scattering of protons accessible at the LHC. A striking prediction of our analysis is that the azimuthal angle of the produced ridges will be correlated with the scattering plane of the electron or proton producing the virtual photon. In the case of \\(ep \\to eX\\), the final state \\(X\\) is expected to exhibit maximal multiplicity when the elliptic flow in \\(X\\) is aligned with the electron scattering plane. In the \\(pp \\to ppX\\) example, the multiplicity and elliptic flow in \\(X\\) are estimated to exhibit correlated oscillations as functions of the azimuthal angle \\(\\Phi\\) between the proton scattering planes. In the minimum-bias event samples, the amplitude of oscillations is expected to be on the order of 2 to 4 percent of the mean values. In the events with highest multiplicity, the oscillations can be three times larger than in the minimum-bias event samples.
Paper
Ridge Production in High-Multiplicity Hadronic Ultra-Peripheral Proton-Proton Collisions
An unexpected result at the RHIC and the LHC is the observation that high-multiplicity hadronic events in heavy-ion and proton-proton collisions are distributed as two \"ridges\", approximately flat in rapidity and opposite in azimuthal angle. We propose that the origin of these events is due to the inelastic collisions of aligned gluonic flux tubes that underly the color confinement of the quarks in each proton. We predict that high-multiplicity hadronic ridges will also be produced in the high energy photon-photon collisions accessible at the LHC in ultra-peripheral proton-proton collisions or at a high energy electron-positron collider. We also note the orientation of the flux tubes between the quark and antiquark of each high energy photon will be correlated with the plane of the scattered proton or lepton. Thus hadron production and ridge formation can be controlled in a novel way at the LHC by observing the azimuthal correlations of the scattering planes of the ultra-peripheral protons with the orientation of the produced ridges. Photon-photon collisions can thus illuminate the fundamental physics underlying the ridge effect and the physics of color confinement in QCD.
Paper
Higgs Hadroproduction at Large Feynman x
We propose a novel mechanism for the production of the Higgs boson in inclusive hadronic collisions, which utilizes the presence of heavy quarks in the proton wave function. In these inclusive reactions the Higgs boson acquires the momenta of both the heavy quark and antiquark and thus carries 80% or more of the projectile's momentum. We predict that the cross section \\({d \\sigma/d x_F}(p \\bar p \\to H X)\\) for the inclusive production of the Standard Model Higgs coming from intrinsic bottom Fock states is of order 150 fb at LHC energies, peaking in the region of \\(x_F \\sim 0.9\\). Our estimates indicate that the corresponding cross section coming from gluon-gluon fusion at \\(x_F = 0.9\\) is relatively negligible and therefore the peak from intrinsic bottom should be clearly visible for experiments with forward detection capabilities. The predicted cross section for the production of the Standard Model Higgs coming from intrinsic heavy quark Fock states in the proton is sufficiently large that detection at the Tevatron and the LHC may be possible.
Paper
First Are Last Fractional-Charge Solitons
Jackiw and Rebbi found two types of intrinsically stable or `fundamental' soliton (kinks in 1+1 D and magnetic monopoles in 3+1 D) which can carry pieces of elementary-particle charges. After two decades there are no more, and it is argued here why that is inevitable.
Paper
Hairs on the Unicorn: Fine Structure of Monopoles and Other Solitons
Intrinsically stable or `fundamental' solitons may be decorated with conserved charges which are pieces of those carried by elementary particles in the same medium. These `hairs' are always significant in principle, and in the strong-coupling regime (where solitons and particles exchange roles) may become major factors in dynamics.
Paper
Solitons with integer fermion number
Necessary and sufficient conditions are found for any object in \\(3+1\\) dimensions to have integer rather than fractional fermion number. Nontrivial examples include the Jackiw-Rebbi monopole and the already well studied Su-Schrieffer-Heeger soliton, both displaying integer multiples of elementary charges in combinations that normally are forbidden.
Paper
Confinement, Crossing Symmetry, and Glueballs
We suggest that the quark-confining force is related by crossing symmetry to a color-singlet glueball \\({\\cal G}\\) which is well described as a loop of one quantum of color magnetic flux. Electron pair annihilation as high as \\(\\approx 2 GeV\\) above the \\(\\Upsilon\\) mass could produce \\(\\Upsilon \\rightarrow \\ell^+\\ell^-\\) accompanied by \\({\\cal G}\\) or one of its excited states.
Paper
Investment in Basic Science
The impending federal decision whether to allow $10 million for construction of Isabelle at Brookhaven National Laboratory [\"Budget Cuts Said to Doom Isabelle Project,\" April 6] will be critical for our region, our state and our nation. Such a modest sum matters so much because a \"yes\" now would carry the strong implication that the several hundred million more dollars needed for completion would be provided as called for in...
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