Polarized proton-neutron total cross sections from proton-deuteron data

Simple expressions are derived for the polarized proton-deuteron total cross sections. Possibilities of extraction of the polarized proton-neutron cross sections from the proton-deuteron data are discussed. 19 references

Strangeness-Conserving Hadronic Parity Violation at Low Energies

The parity-violating nucleon-nucleon interaction is the key to understanding the strangeness-conserving hadronic weak interaction at low energies. In this brief talk, I review the past accomplishments in and current status of this subject, and outline a new joint effort between experiment and theory that tries to address the potential problems in the past by focusing on parity violation in few-nucleon systems and using the language of effective field theory.Comment: 8 pages, to appear in the proceedings of the Second Meeting of the APS Topical Group on Hadronic Physics, Nashville, TN, USA, Oct. 22-24, 200

Evidence for Color Fluctuations in Hadrons from Coherent Nuclear Diffraction}

A QCD-based treatment of projectile size fluctuations is used to compute inelastic diffractive cross sections $\sigma_{diff}$ for coherent hadron-nuclear processes. We find that fluctuations near the average size give the major contribution to the cross section with $\le few \%$ contribution from small size configurations. The computed values of $\sigma_{diff}$ are consistent with the limited available data. The importance of coherent diffraction studies for a wide range of projectiles for high energy Fermilab fixed target experiments is emphasized. The implications of these significant color fluctuations for relativistic heavy ion collisions are discussed.Comment: Report number DOE/ER 40427-13-N93 11 pages, 3 figures available from author Mille

Parity Violation in gamma proton Compton Scattering

A measurement of parity-violating spin-dependent gamma proton Compton scattering will provide a theoretically clean determination of the parity-violating pion-nucleon coupling constant $h_{\pi NN}^{(1)}$. We calculate the leading parity-violating amplitude arising from one-loop pion graphs in chiral perturbation theory. An asymmetry of ~5 10^{-8} is estimated for Compton scattering of 100 MeV photons.Comment: 6 pages, 1 figure, latex. Reference adde

Probing Short Range Nucleon Correlations in High Energy Hard Quasielastic pd Reactions

We show that the strong dependence of the amplitude for $NN$ hard scattering on the collision energy can be used to magnify the effects of short range nucleon correlations in quasielastic $pd$ scattering. Under specific kinematical conditions the effect of initial and final state interactions can be accounted for by rescaling the cross section calculated within the plane wave impulse approximation. The feasibility to investigate the role of relativistic effects in the deuteron wave function is demonstrated by comparing the predictions of different formalisms. Binding effects due to short range correlations in deuteron are discussed as well.Comment: 18 pages (LaTex) + 10 postscript figs (available on request

Dijet production as a centrality trigger for p-p collisions at CERN LHC

We demonstrate that a trigger on hard dijet production at small rapidities allows to establish a quantitative distinction between central and peripheral collisions in pbar-p and p-p collisions at Tevatron and LHC energies. Such a trigger strongly reduces the effective impact parameters as compared to minimum bias events. This happens because the transverse spatial distribution of hard partons (x >~ 10^{-2}) in the proton is considerably narrower than that of soft partons, whose collisions dominate the total cross section. In the central collisions selected by the trigger, most of the partons with x >~ 10^{-2} interact with a gluon field whose strength rapidly increases with energy. At LHC (and to some extent already at Tevatron) energies the strength of this interaction approaches the unitarity ('black-body') limit. This leads to specific modifications of the final state, such as a higher probability of multijet events at small rapidities, a strong increase of the transverse momenta and depletion of the longitudinal momenta at large rapidities, and the appearance of long-range correlations in rapidity between the forward/backward fragmentation regions. The same pattern is expected for events with production of new heavy particles (Higgs, SUSY). Studies of these phenomena would be feasible with the CMS-TOTEM detector setup, and would have considerable impact on the exploration of the physics of strong gluon fields in QCD, as well as the search for new particles at LHC.Comment: 17 pages, Revtex 4, 14 EPS figures. Expanded discussion of some points, added 3 new figures and new references. Included comment on connection with cosmic ray physics near the GZK cutoff. To appear in Phys Rev

Quadrupole deformation of deuterons and final state interaction in 2H⃗(e,e′p)^2 \vec H (e,e'p) scattering on tensor polarized deuterons at CEBAF energies

The strength of final state interaction (FSI) between struck proton and spectator neutron in $^2\vec{H}(e,e'p)$ scattering depends on the alignment of the deuteron. We study the resulting FSI effects in the tensor analyzing power in detail and find substantial FSI effects starting at still low missing momentum p_m \gsim 0.9 fm^{-1}. At larger p_m \gsim 1.5 fm^{-1}, FSI completely dominates both missing momentum distribution and tensor analyzing power. We find that to a large extent FSI masks the sensitivity of the tensor analyzing power to models of the deuteron wave function. For the transversely polarized deuterons the FSI induced forward-backward asymmetry of the missing momentum distribution is shown to have a node at precisely the same value of $p_m$ as the PWIA missing momentum distribution. The position of this node is not affected by FSI and can be a tool to distinguish experimentally between different models for the deuteron wave function.Comment: 24 pages, figures available from the authors on reques

Elastic Nd scattering at intermediate energies as a tool for probing the short-range deuteron structure

A calculation of the deuteron polarization observables $A^d_y$, $A_{yy}$, $A_{xx}$, $A_{xz}$ and the differential cross-section for elastic nucleon-deuteron scattering at incident deuteron energies 270 and 880 MeV in lab is presented. A comparison of the calculations with two different deuteron wave-functions derived from the Bonn-CD $NN$-potential model and the dressed bag quark model is carried out. A model-independent approach, based on an optical potential framework, is used in which a nucleon-nucleon $T$-matrix is assumed to be local and taken on the energy shell, but still depends on the internal nucleon momentum in a deuteron.Comment: 15 pages, 4 figure

Thermal Properties of an Inflationary Universe

An energetic justification of a thermal component during inflation is given. The thermal component can act as a heat reservoir which induces thermal fluctuations on the inflaton field system. We showed previously that such thermal fluctuations could dominate quantum fluctuations in producing the initial seeds of density perturbations. A Langevin-like rate equation is derived from quantum field theory which describes the production of fluctuations in the inflaton field when acted upon by a simple modeled heat reservoir. In a certain limit this equation is shown to reduce to the standard Langevin equation, which we used to construct "Warm Inflation" scenarios in previous work. A particle physics interpretation of our system-reservoir model is offered.Comment: 28 pages, 0 figures, In Press Physical Review D 199

Reggeon and pion contributions in semi-exclusive diffractive processes at HERA

A detailed analysis of semi-exclusive diffractive processes in e-p DIS at HERA, with the diffractive final states in the forward direction is presented. The contributions of the subleading f_2, \omega, a_2, \rho reggeons and the pion exchanges to the diffractive structure function with the forward proton or neutron are estimated. It is found that the (a_2,\rho) reggeons are entirely responsible for the forward neutron production at x_P < 10^{-3}. The \pi N production in the forward region is estimated using the Deck mechanism. The significance of this reaction for the processes measured at HERA, especially with the leading neutron, is discussed.Comment: Strongly revised version accepted for publication in Phys.Rev.D. Latex, 14 pages with 5 eps figures include