arXiv subjects

Mathias Butenschoen

Publications and source records attributed to Mathias Butenschoen.

25 records · Page 2Linked to original sources

arXiv2011

Reconciling J/psi production at HERA, RHIC, Tevatron, and LHC with NRQCD factorization at next-to-leading order

We calculate the cross section of inclusive direct J/psi hadroproduction at next-to-leading order (NLO) within the factorization formalism of nonrelativistic quantum chromodynamics (NRQCD), including the full relativistic corrections due to the intermediate 1S_0^[8], 3S_1^[8], and 3P_J^[8] color-octet states. We perform a combined fit of the color-octet (CO) long-distance matrix elements to the transverse-momentum (p_T) distributions measured by CDF at the Fermilab Tevatron and H1 at DESY HERA and demonstrate that they also successfully describe the p_T distributions from PHENIX at BNL RHIC and CMS at the CERN LHC as well as the photon-proton c.m. energy and (with worse agreement) the inelasticity distributions from H1. This provides a first rigorous test of NRQCD factorization at NLO. In all experiments, the CO processes are shown to be indispensable.

hep-ph↗

arXiv2010

J/psi production with NRQCD: HERA, Tevatron, RHIC and LHC

We report on our recent calculation of the inclusive direct photo- and hadroproduction of the J/psi meson at next-to-leading order within the factorization formalism of nonrelativistic QCD. We fit the color-octet (CO) long-distance matrix elements , and to the transverse momentum (p_T) distributions measured by CDF at Fermilab Tevatron and by H1 at DESY HERA and show that they also successfully describe the p_T distributions from PHENIX at BNL RHIC and CMS at the CERN LHC as well as the photon-proton c.m. energy and (with worse agreement) the inelasticity distributions from H1. In all experiments, the CO processes are shown to be indispensable.

hep-ph↗

arXiv2010

J/psi production in ep collisions at HERA

This report is a short overview of experimental and theoretical results in J/psi production in electron-proton collisions at DESY HERA with special focus lying on recent developments in inelastic photoproduction.

hep-ph↗

arXiv2010

Direct J/psi photoproduction at next-to-leading-order in nonrelativistic QCD

We calculate the cross section of inclusive direct J/psi photoproduction at next-to-leading order within the factorization formalism of nonrelativistic quantum chromodynamics, for the first time including the full relativistic corrections due to the intermediate ^1S_0^{[8]}, ^3S_1^{[8]}, and ^3P_J^{[8]} color-octet states. A comparison of our results to recent H1 data suggests that the color octet mechanism is indeed realized in J/psi photoproduction, although the predictivity of our results still suffers from uncertainties in the color-octet long-distance matrix elements.

hep-ph↗

arXiv2010

Complete next-to-leading-order corrections to J/psi photoproduction in nonrelativistic quantum chromodynamics

We calculate the cross section of inclusive direct J/psi photoproduction at next-to-leading order within the factorization formalism of nonrelativistic quantum chromodynamics, for the first time including the full relativistic corrections due to the intermediate ^1S_0^[8], ^3S_1^[8], and ^3P_J^[8] color-octet states. A comparison of our results to recent H1 data suggests that the color octet mechanism is indeed realized in J/psi photoproduction, although the predictivity of our results still suffers from uncertainties in the color-octet long-distance matrix elements.

hep-ph↗

arXiv2007

O(G_F^2 m_t^4) two-loop electroweak correction to Higgs-boson decay to bottom quarks

We analytically calculate the dominant two-loop electroweak correction, of O(G_F^2 m_t^4), to the partial width of the decay of a Higgs boson, with mass M_H << m_t, into a bottom-quark pair, and describe the most important conceptual and technical details of our calculation. As a by-product of our analysis, we also recover the O(alpha_s G_F m_t^2) correction. Relative to the Born result, the O(G_F^2 m_t^4) correction turns out to be approximately +0.047% and, thus, more than compensates the O(alpha_s G_F m_t^2) one, which amounts to approximately -0.022%.

hep-ph↗

arXiv2006

Two-loop virtual top-quark effect on Higgs-boson decay to bottom quarks

In most of the mass range encompassed by the limits from the direct search and the electroweak precision tests, the Higgs boson of the standard model preferably decays to bottom quarks. We present, in analytic form, the dominant two-loop electroweak correction, of O(G_F^2 m_t^4), to the partial width of this decay. It amplifies the familiar enhancement due to the O(G_F m_t^2) one-loop correction by about +16% and thus more than compensates the screening by about -8% through strong-interaction effects of order O(alpha_s G_F m_t^2).

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