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*TAUP* *2501-98* *hep*- *ph*/9806228

, 1998

"... The BFKL high energy asymptotics in the next-to-leading approximation ..."

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*TAUP*-2342-96 *hep-ph*/9606284

, 1996

"... Passage of charmed particles through the mixed phase in high-energy heavy-ion collisions ..."

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Passage of charmed particles through the mixed phase in high-energy heavy-ion collisions

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*TAUP* 2462-97.B *hep-ph*/9710302 Asymptotic Padé Approximant Predictions: up to Five Loops in QCD and SQCD

, 1997

"... We use Asymptotic Padé Approximants (APAP’s) to predict the four- and five-loop β functions in QCD and N = 1 supersymmetric QCD (SQCD), as well as the quark mass anomalous dimensions in Abelian and non-Abelian gauge theories. We show how the accuracy of our previous β-function predictions at the fou ..."

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We use Asymptotic Padé Approximants (APAP’s) to predict the four- and five-loop β functions in QCD and N = 1 supersymmetric QCD (SQCD), as well as the quark mass anomalous dimensions in Abelian and non-Abelian gauge theories. We show how the accuracy of our previous β-function predictions at the four-loop level may be further improved by using estimators weighted over negative numbers of flavours (WAPAP’s). The accuracy of the improved four-loop results encourages confidence in the new five-loop β-function predictions that we present. However, the WAPAP approach does not provide improved results for the anomalous mass dimension, or for Abelian theories.

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*TAUP*-2273-95, *hep-ph*/9507218 THE NUCLEON’S VIRTUAL MESON CLOUD AND DEEP INELASTIC LEPTON SCATTERING

, 1995

"... We address the question whether the nucleon’s antiquark sea can be attributed entirely to its virtual meson cloud and, in essence, whether there exists a smooth transition between hadronic and quark-gluon degrees of freedom. We take into account contributions from π and K mesons and compare with the ..."

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We address the question whether the nucleon’s antiquark sea can be attributed entirely to its virtual meson cloud and, in essence, whether there exists a smooth transition between hadronic and quark-gluon degrees of freedom. We take into account contributions from π and K mesons and compare with the nucleon’s antiquark distributions which serve as a non-perturbative input to the QCD evolution equations. We elucidate the different behavior in the flavor singlet and non-singlet channels and study the dependence of our results on the scale Q2. The meson-nucleon cut-offs that we determine

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*TAUP*-2290-95, *hep-ph*/9509311 Hard diffractive electroproduction of vector mesons in QCD

, 1996

"... in print by Phys. Rev. D Hard diffractive electroproduction of longitudinally polarized vector mesons is calculated within the leading αs ln Q2 Λ2 approximation of QCD using the QCD leading order parton densities within the nucleon. Novel QCD features of the production of excited states and of the r ..."

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in print by Phys. Rev. D Hard diffractive electroproduction of longitudinally polarized vector mesons is calculated within the leading αs ln Q2 Λ2 approximation of QCD using the QCD leading order parton densities within the nucleon. Novel QCD features of the production of excited states and of the restoration of flavor symmetry are analyzed. At the onset of the asymptotic regime, our analysis finds an important role of quark Fermi motion within the diffractively produced vector mesons, and we suggest to use this effect to measure the high momentum tail of the wave function of the vector mesons. We deduce a kinematical boundary for the region of applicability of the decomposition of the hard

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*TAUP*-2298-95, *hep-ph*/9510452 THE NUCLEON’S ANTIQUARK SEA: A VIRTUAL MESON CLOUD OR GLUONS?

, 1995

"... We study the possible contribution of the nucleon’s virtual meson cloud to the sea quark distribution as observed in deep inelastic lepton scattering. We adjust the meson-nucleon cut-offs to the large-x tails of the antiquark distributions, find qualitatively different behavior in the flavor singlet ..."

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We study the possible contribution of the nucleon’s virtual meson cloud to the sea quark distribution as observed in deep inelastic lepton scattering. We adjust the meson-nucleon cut-offs to the large-x tails of the antiquark distributions, find qualitatively different behavior in the flavor singlet and non-singlet channels and study the scale dependence of our results. We demonstrate that, within convolution models, to reproduce the sea quark distribution the relevant pion momenta should be around 0.8 GeV. 1 The Nucleon’s Meson Cloud and Deep Inelastic Lepton Scattering In this realm, the nucleon is pictured as being part of the time a bare core and part of the time a baryon with one meson ”in the air”, |N 〉 = √ Z |N0 〉 + ∑ gMNB|BM 〉. (1) The wave function renormalization factor, √ Z, only affects the core because physical (renormalized) and not bare couplings were used [1]. Thus, we keep the conventional value for the πNN coupling constant, which follows unambigously from dispersion relations for the πN amplitude. In this point our approach differs from other prescriptions [2] where a renormalization of the πNN coupling constant has been introduced. The meson cloud contribution to the nucleon’s antiquark sea can be written as, x ¯qN(x, Q 2) = ∑ M,B M α q

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*TAUP* 2735-03 *hep-ph*/0307243 The Constituent Quark Model Revisited- Quark Masses, New Predictions for Hadron Masses

, 2003

"... Prompted by the recent surprising results in QCD spectroscopy, we extend to heavy flavors the hadron mass relations showing that the constituent quark mass differences and ratios have the same values when obtained from mesons and baryons. We obtain several new successful relations involving heavy qu ..."

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Prompted by the recent surprising results in QCD spectroscopy, we extend to heavy flavors the hadron mass relations showing that the constituent quark mass differences and ratios have the same values when obtained from mesons and baryons. We obtain several new successful relations involving heavy quarks and provide some related predictions. We discuss in detail the apparent sharp decrease in ms and mc, when a light partner quark in a meson is replaced by a heavy one and construct a potential model which qualitatively reproduces this pattern through wave function effects. We apply these ideas to the recently discovered θ + exotic KN resonance and propose its interpretation as a novel kind of a pentaquark with an unusual color structure, J P = 1/2 +, I = 0 and an antidecuplet of SU(3)f. A rough mass estimate of this pentaquark is close to experiment.

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*TAUP* 2346-96 *hep-ph*/9607201 Flavor Oscillations from a Spatially Localized Source A Simple General Treatment

, 1996

"... A unique description avoiding confusion is presented for all flavor oscillation experiments in which particles of a definite flavor are emitted from a localized source. The probability for finding a particle with the wrong flavor must vanish at the position of the source for all times. This conditio ..."

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A unique description avoiding confusion is presented for all flavor oscillation experiments in which particles of a definite flavor are emitted from a localized source. The probability for finding a particle with the wrong flavor must vanish at the position of the source for all times. This condition requires flavor–time and flavor–energy factorizations which determine uniquely the flavor mixture observed at a detector in the oscillation region; i.e. where the overlaps between the wave packets for different mass eigenstates are almost complete. Oscillation periods calculated for “gedanken ” time-measurement experiments are shown to give the correct measured oscillation wave length in space when multiplied by the group velocity. Examples of neutrinos propagation in a weak field and in a gravitational field are given. In these cases the relative phase is modified differently for measurements in space and time. Energy-momentum (frequency-wave number) and space-time descriptions are complementary, equally valid and give the same results. The two identical phase shifts obtained describe the same physics; adding them together to get a factor of two is double counting. 1 I.