A new gamma*-p / pbar-p factorization test in diffraction, valid below Q^2 about 6 GeV^2

One of the key experimental issues in high energy hadron physics is the extent to which data from the diffractive interaction mechanism may be described by a factorized formula which is the product of a universal term describing the probability of finding a Pomeron in a proton (loosely referred to as the "Pomeron flux-factor") and a term decribing the Pomeron's interaction with the other incident proton. In the present paper, after demonstrating that existing data on diffractive gamma*-p and pbar-p interactions show that the Pomeron flux-factor is not universal, we present the results of a new test of factorization in these interactions which does not rely on universality of the flux-factor. The test is satisfied to within ~20% for 1 < Q^2 ~ 6 GeV^2 and beta < 0.2 in the gamma*-p interactions, suggesting that the resons for non-universality of the flux-factor have a limited effect on the factorization itself. However, a clear breakdown of this test is observed at larger Q^2. Kharzeev and Levin suggest that this can be attributed to the onset of QCD evolution effects in the Pomeron's structure. The breakdown occurs in a Q^2 region which agrees with their estimates of a small Pomeron size.Comment: 20 pages, 7 Encapsulated Postscript figures, LaTex, submitted to European Phisical Journal

Open Charm Production at HERA

Measurements of charmed particle cross sections at HERA in the photoproduction and deep inelastic regimes are reviewed. The status of the comparison with perturbative QCD calculations is discussed.Comment: Presented at the Ringberg Workshop on ``New Trends in HERA Physics 2001'' 17-22 June 2001. 12 pages, 11 figure

Measurement of Orbitally Excited D-Mesons at CDF II

Measurement of Orbitally Excited D-Mesons at CDF II Igor V. Gorelov (For the CDF Collaboration) Talk given on behalf of the CDF Collaboration at the First Meeting of the APS Topical Group on Hadronic Physics, GHP 2004, 24-26 October 2004, FERMILAB. Results on the first measurement of orbitally excited neutral D-meson states, D*_2 and D_1, produced in hadron collisions at Tevatron are presented. Using data from the displaced track trigger, CDF II collects the largest world sample of these states in decay modes D*+ pi-, D+ pi-. Masses and widths of both states have been measured with precision better than or comparable to the world average.Comment: 6 pages, 5 figures, talk given on behalf of the CDF Collaboration at the First Meeting of the APS Topical Group on Hadronic Physics, GHP 2004, Oct 24-26,2004, Fermilab, Batavia, Illinoi

Isocurvature forecast in the anthropic axion window

We explore the cosmological sensitivity to the amplitude of isocurvature fluctuations that would be caused by axions in the "anthropic window" where the axion decay constant f_a >> 10^12 GeV and the initial misalignment angle Theta_i << 1. In a minimal Lambda-CDM cosmology extended with subdominant scale-invariant isocurvature fluctuations, existing data constrain the isocurvature fraction to alpha < 0.09 at 95% C.L. If no signal shows up, Planck can improve this constraint to 0.042 while an ultimate CMB probe limited only by cosmic variance in both temperature and E-polarisation can reach 0.017, about a factor of five better than the current limit. In the parameter space of f_a and H_I (Hubble parameter during inflation) we identify a small region where axion detection remains within the reach of realistic cosmological probes.Comment: 14 pages, 4 figures; v2: matches published versio

Flavor SU(3) analysis of charmless B meson decays to two pseudoscalar mesons

Global fits to charmless B --> PP decays in the framework of flavor SU(3) symmetry are updated and improved without reference to the \sin2\beta measured from the charmonium decay modes. Fit results directly constrain the (\bar\rho,\bar\eta) vertex of the unitarity triangle, and are used to predict the branching ratios and CP asymmetries of all decay modes, including those of the B_s system. Different schemes of SU(3) breaking in decay amplitude sizes are analyzed. The major breaking effect between strangeness-conserving and strangeness-changing decays can be accounted for by including a ratio of decay constants in tree and color-suppressed amplitudes. The possibility of having a new physics contribution to K \pi decays is also examined from the data fitting point of view.Comment: 22 pages and 2 figures; some comments and references added; more references added, version to appear in journa

Centrality and sNNDependenceofthe\sqrt{s_{NN}} Dependence of the dE_{T}/d\etaand and dN_{ch}/d\eta$ in Heavy Ion Collisions at Mid-Rapidity

The PHENIX experiment at RHIC has measured transverse energy and charged particle multiplicity at mid-rapidity in Au + Au collisions at $\sqrt{s_{NN}}$ = 19.6, 130, 62.4 and 200 GeV as a function of centrality. The presented results are compared to measurements from other RHIC experiments, and experiments at lower energies. The $\sqrt{s_{NN}}$ dependence of $dE_{T}/d\eta$ and $dN_{ch}/d\eta$ per pair of participants is consistent with logarithmic scaling for the most central events. The centrality dependence of $dE_{T}/d\eta$ and $dN_{ch}/d\eta$ is similar at all measured incident energies. At RHIC energies the ratio of transverse energy per charged particle was found independent of centrality and growing slowly with $\sqrt{s_{NN}}$. A survey of comparisons between the data and available theoretical models is also presented.Comment: Proccedings of the Workshop: Focus on Multiplcity at Bari, Italy, June 17-19,2004. To be submitted to the Jornal of Physics, "Conference series". Includes: 20 Pages, 15 figures, 3 Tables, 80 Referencie

Cosmological CPT Violation and CMB Polarization Measurements

In this paper we study the possibility of testing Charge-Parity-Time Reversal (CPT) symmetry with cosmic microwave background (CMB) experiments. We consider two kinds of Chern-Simons (CS) term, electromagnetic CS term and gravitational CS term, and study their effects on the CMB polarization power spectra in detail. By combining current CMB polarization measurements, the seven-year WMAP, BOOMERanG 2003 and BICEP observations, we obtain a tight constraint on the rotation angle $\Delta\alpha=-2.28\pm1.02$ deg ($1\,\sigma$), indicating a $2.2\,\sigma$ detection of the CPT violation. Here, we particularly take the systematic errors of CMB measurements into account. After adding the QUaD polarization data, the constraint becomes $-1.34<\Delta\alpha<0.82$ deg at 95% confidence level. When comparing with the effect of electromagnetic CS term, the gravitational CS term could only generate TB and EB power spectra with much smaller amplitude. Therefore, the induced parameter $\epsilon$ can not be constrained from the current polarization data. Furthermore, we study the capabilities of future CMB measurements, Planck and CMBPol, on the constraints of $\Delta\alpha$ and $\epsilon$. We find that the constraint of $\Delta\alpha$ can be significantly improved by a factor of 15. Therefore, if this rotation angle effect can not be taken into account properly, the constraints of cosmological parameters will be biased obviously. For the gravitational CS term, the future Planck data still can not constrain $\epsilon$ very well, if the primordial tensor perturbations are small, $r <0.1$. We need the more accurate CMBPol experiment to give better constraint on $\epsilon$.Comment: 11 pages, 5 figures, 4 tables, Accepted for publication in JCA

Determination of the longitudinal structure function FLF_{L} at HERA

Recent results from the HERA experiment H1 on the longitudinal stucture function $F_{L}$ of the proton are presented. They include proton structure function analyses with particular emphasis on those kinematic regions which are sensitive to $F_{L}$. All results can be consistently described within the framework of perturbative QCD.Comment: 16 pages, 11 figures (requires iopart, iopams and epsfig); Talk presented in the Intern. Workshop on New Trends in HERA Physics 2001, 17-22 June 2001, Ringberg Castle, Tegernsee, Germany; To appear in the Proceeding

Heavy Quark Spectroscopy -- Theory Overview

Some recent discoveries in the spectroscopy of hadrons containing heavy quarks, and some of their theoretical interpretations, are reviewed.Comment: 13 pages, 6 figures. Presented at Second Meeting of APS Topical Group on Hadron Physics, Nashville, TN, 22-24. Proceedings to be published by Journal of Physics (UK), Conference Series. Uses jpconf.cls, jpconf11.clo. Some corrections; references update