Higher-Order Corrections to Radiative Upsilon Decays

Recent advances in the theoretical description of radiative Upsilon decays are reviewed, including the calculation of next-to-leading order QCD corrections to the photon spectrum.Comment: LaTeX, 10 pages, 5 Postscript figures, uses sprocl.sty. Talk presented at the IVth International Symposium on Radiative Corrections (RADCOR 98), Barcelona, September 8-12, 1998, to appear in the proceeding

Inelastic J/ψJ/\psi photoproduction

Inelastic photoproduction of $J/\psi$ particles at high energies is one of the processes to determine the gluon distribution in the nucleon. The QCD radiative corrections to the color-singlet model of this reaction have recently been calculated. They are large at moderate photon energies, but decrease with increasing energies. I compare the cross section and the ${J/\psi}$ energy spectrum with the available fixed-target photoproduction data. Predictions for the HERA energy range are given which demonstrate the sensitivity of the result to the parametrization of the gluon distribution in the small-$x$ region. (Talk presented at the Workshop on "Heavy Quark Physics", Bad Honnef, FRG, Dec. 1994)Comment: 11 pages, LaTeX; figures are included via epsfig; the corresponding postscript files are uuencode

Novel dark matter constraints from antiprotons in the light of AMS-02

We evaluate dark matter (DM) limits from cosmic-ray antiproton observations using the recent precise AMS-02 measurements. We properly take into account cosmic-ray propagation uncertainties fitting at the same time DM and propagation parameters, and marginalizing over the latter. We find a significant (~4.5 sigma) indication of a DM signal for DM masses near 80 GeV, with a hadronic annihilation cross-section close to the thermal value, sigma v ~3e-26 cm3s-1. Intriguingly, this signal is compatible with the DM interpretation of the Galactic center gamma-ray excess. Confirmation of the signal will require a more accurate study of the systematic uncertainties, i.e., the antiproton production cross-section, and modelling of the solar modulation effect. Interpreting the AMS-02 data in terms of upper limits on hadronic DM annihilation, we obtain strong constraints excluding a thermal annihilation cross-section for DM masses below about 50 GeV and in the range between approximately 150 and 500 GeV, even for conservative propagation scenarios. Except for the range around 80 GeV, our limits are a factor 4 stronger than the limits from gamma-ray observations of dwarf galaxies.Comment: 6 pages + 3 of supplemental material, 7 figures, 1 tables. Matches version published on physical review letter

Constraining heavy dark matter with cosmic-ray antiprotons

Cosmic-ray observations provide a powerful probe of dark matter annihilation in the Galaxy. In this paper we derive constraints on heavy dark matter from the recent precise AMS-02 antiproton data. We consider all possible annihilation channels into pairs of standard model particles. Furthermore, we interpret our results in the context of minimal dark matter, including higgsino, wino and quintuplet dark matter. We compare the cosmic-ray antiproton limits to limits from $\gamma$-ray observations of dwarf spheroidal galaxies and to limits from $\gamma$-ray and $\gamma$-line observations towards the Galactic center. While the latter limits are highly dependent on the dark matter density distribution and only exclude a thermal wino for cuspy profiles, the cosmic-ray limits are more robust, strongly disfavoring the thermal wino dark matter scenario even for a conservative estimate of systematic uncertainties.Comment: 14 pages + references, 5 figures; v2: HESS limits added in Fig. 2, matches published versio

Tests of QCD: Summary of DIS 2000

This summary of the working group 2 of DIS 2000 encompasses experimental and theoretical results of jet physics, open and bound state heavy flavour production, prompt photon production, next-to-leading order QCD calculations and beyond, instantons, fragmentation, event shapes, and power corrections, primarily from deep-inelastic scattering and photoproduction at HERA, but also from the LEP and Tevatron colliders.Comment: 16 pages, LaTeX, including 8 PostScript figures. Talk given at the 8th International Workshop on Deep-Inelastic Scattering (DIS2000), 25th-30th April 2000, Liverpool, England, to appear in the proceeding

Probing dark matter annihilation in the Galaxy with antiprotons and gamma rays

A possible hint of dark matter annihilation has been found in Cuoco, Korsmeier and Kr\"amer (2017) from an analysis of recent cosmic-ray antiproton data from AMS-02 and taking into account cosmic-ray propagation uncertainties by fitting at the same time dark matter and propagation parameters. Here, we extend this analysis to a wider class of annihilation channels. We find consistent hints of a dark matter signal with an annihilation cross-section close to the thermal value and with masses in range between 40 and 130 GeV depending on the annihilation channel. Furthermore, we investigate in how far the possible signal is compatible with the Galactic center gamma-ray excess and recent observation of dwarf satellite galaxies by performing a joint global fit including uncertainties in the dark matter density profile. As an example, we interpret our results in the framework of the Higgs portal model.Comment: 12 pages + references, 4 figures, v2: References added, minor changes in presentation, matches journal versio

Constraints on models with universal extra dimensions from dilepton searches at the LHC

Models with universal extra dimensions predict that each Standard Model particle is accompanied by a tower of Kaluza-Klein resonances. Canonical searches for the production and cascade decays of first Kaluza-Klein modes through missing transverse momentum signatures suffer in general from low detection efficiencies because of the rather compressed Kaluza-Klein particle mass spectrum. Here, instead we analyze signatures from the production of second Kaluza-Klein states which can decay into Standard Model particles and thus do not result in any missing transverse momentum. Such signatures provide a strong sensitivity, and are of particular interest as they would allow for a clear distinction between extra dimension models and other models of new physics like supersymmetry. We constrain the production of second Kaluza-Klein particles from recent LHC searches for dilepton resonances, and place limits on the compactification scale to be larger than 715GeV, and on the masses of the second Kaluza-Klein particles to be larger than 1.4TeV.Comment: 11 pages, 4 figures, analysis updated (inclusion of data from CMS-PAS-EXO-12-061), MUED bound improved to R^{-1} > 715 GeV, version published in JHE

D* Production in Two-Photon Collisions

We calculate total and differential production rates of D* mesons in two-photon collisions at LEP2. We include full next-to-leading order QCD corrections, and perform an extensive study of the sensitivity of our predictions to variations of the renormalization scale, charm mass, photonic parton distribution set and fragmentation function. The results are compared with recent data from LEP2.Comment: Latex, 19 pages, 9 figure