0000000001210106
AUTHOR
H. Spiesberger
showing 18 related works from this author
Inclusive B-meson production at small p_T in the general-mass variable-flavor-number scheme
2015
We calculate the cross section for the inclusive production of B mesons in pp and ppbar collisions at next-to-leading order in the general-mass variable-flavor-number scheme and show that a suitable choice of factorization scales leads to a smooth transition to the fixed-flavor-number scheme. Our numerical results are in good agreement with data from the Tevatron and LHC experiments at small and at large transverse momenta.
$\Lambda_b^0$-baryon production in pp collisions in the general-mass variable-flavour-number scheme and comparison with CMS and LHCb data
2018
We calculate the next-to-leading-order cross section for the inclusive production of $\Lambda_b$ baryons in pp collisions in the general-mass variable-flavor-number scheme. We use realistic evolved non-perturbative fragmentation functions obtained from fits to B-meson production in $e^+ e^-$ annihilation and compare our results for transverse-momentum and rapidity distributions with recent experimental data from the CMS and the LHCb collaborations at the CERN LHC. We find satisfactory agreement in general, with some indication for the need to modify the available fragmentation functions at larger values of the scale variable.
Running of the Charm-Quark Mass from HERA Deep-Inelastic Scattering Data
2017
Physics letters / B 775, 233 - 238 (2017). doi:10.1016/j.physletb.2017.11.002
How strange is pion electroproduction?
2015
We consider pion production in parity-violating electron scattering (PVES) in the presence of nucleon strangeness in the framework of partial wave analysis with unitarity. Using the experimental bounds on the strange form factors obtained in elastic PVES, we study the sensitivity of the parity-violating asymmetry to strange nucleon form factors. For forward kinematics and electron energies above 1 GeV, we observe that this sensitivity may reach about 20\% in the threshold region. With parity-violating asymmetries being as large as tens p.p.m., this study suggests that threshold pion production in PVES can be used as a promising way to better constrain strangeness contributions. Using this m…
Reduced uncertainty of the axial γZ-box diagram correction to the proton’s weak charge
2019
We present the fully up-to-date calculation of the γZ-box correction which needs to be taken into account to determine the weak mixing angle at low energies from parity-violating electron proton scattering. We make use of neutrino and antineutrino inclusive scattering data to predict the parity-violating structure function F3γZ by isospin symmetry. Our new analysis confirms previous results for the axial contribution to the γZ-box graph and reduces the uncertainty by a factor of 2. In addition, we note that the presence of parity-violating photon-hadron interactions induces an additional contribution via F3γγ. Using experimental and theoretical constraints on the nucleon anapole moment we a…
Inclusive photoproduction of bottom quarks for low and medium p T in the general-mass variable-flavour-number scheme
2016
We present predictions for b-quark production in photoprodcution and compare with experimental data from HERA. Our theoretical predictions are obtained at next-to-leading-order in the general-mass variable-flavor-number scheme, an approach which takes into account the finite mass of the b quarks. We use realistic evolved nonperturbative fragmentation functions obtained from fits to e+e- data. We find in general good agreement of data with both the GM-VFNS and the FFNS calculations, while the more precise ZEUS data seem to prefer the GM-VFNS predictions.
D* Mesons in photoproduction at HERA
2009
Ringberg Workshop on New Trends in HERA Physics 2008, Ringberg Castle, Germany, 5 Oct 2008 - 10 Oct 2008; Nuclear physics <Amsterdam> / B / Proceedings supplements 191, 183 - 192 (2009). doi:10.1016/j.nuclphysbps.2009.03.125
Tests of quark-hadron duality in tau-decays
2016
An exhaustive number of QCD finite energy sum rules for $\tau$-decay together with the latest updated ALEPH data is used to test the assumption of global duality. Typical checks are the absence of the dimension $d=2$ condensate, the equality of the gluon condensate extracted from vector or axial vector spectral functions, the Weinberg sum rules, the chiral condensates of dimensions $d=6$ and $d=8$, as well as the extraction of some low-energy parameters of chiral perturbation theory. Suitable pinched linear integration kernels are introduced in the sum rules in order to suppress potential quark-hadron duality violations and experimental errors. We find no compelling indications of duality v…
Study of heavy meson production in p–Pb collisions atS=5.02TeV in the general-mass variable-flavour-number scheme
2017
Abstract We study inclusive charm and bottom production, for both D and B mesons, in p–Pb collisions at the LHC. Numerical results for p T -differential production cross sections are obtained at next-to-leading-order in the general-mass variable-flavour-number scheme. We compare our results with recent data from ALICE, LHCb and CMS at a centre-of-mass energy of 5 TeV and find good agreement. A comparison with p–p cross sections does not reveal the presence of nuclear initial-state interaction effects that could be expected to become visible as deviations of the ratio of p–Pb and p–p cross sections from one.
b-Hadron production in the general-mass variable-flavour-number scheme and LHC data
2018
We study inclusive b-hadron production in pp collisions at the LHC at different center-of-mass energies and compare with experimental data from the LHCb and CMS collaborations. Our predictions for cross sections differential in the transverse momentum and (pseudo-)rapidity agree with data within uncertainties due to renormalization scale variations. A small tension is found if data and theory predictions are compared for cross section ratios at different center-of-mass energies.
Quark–hadron duality: Pinched kernel approach
2016
Hadronic spectral functions measured by the ALEPH collaboration in the vector and axial-vector channels are used to study potential quark-hadron duality violations (DV). This is done entirely in the framework of pinched kernel finite energy sum rules (FESR), i.e. in a model independent fashion. The kinematical range of the ALEPH data is effectively extended up to $s = 10\; {\mbox{GeV}^2}$ by using an appropriate kernel, and assuming that in this region the spectral functions are given by perturbative QCD. Support for this assumption is obtained by using $e^+ e^-$ annihilation data in the vector channel. Results in both channels show a good saturation of the pinched FESR, without further nee…
Anomalous magnetic moment of the muon: A hybrid approach
2017
A new QCD sum rule determination of the leading order hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon, $a_{\mu}^{\rm hvp}$, is proposed. This approach combines data on $e^{+}e^{-}$ annihilation into hadrons, perturbative QCD and lattice QCD results for the first derivative of the electromagnetic current correlator at zero momentum transfer, $\Pi_{\rm EM}^\prime(0)$. The idea is based on the observation that, in the relevant kinematic domain, the integration kernel $K(s)$, entering the formula relating $a_{\mu}^{\rm hvp}$ to $e^{+}e^{-}$ annihilation data, behaves like $1/s$ times a very smooth function of $s$, the squared energy. We find an expression …
Inclusive D-Meson Production at the LHC
2012
I present predictions for the inclusive production of $D$ mesons at the CERN LHC in the general-mass variable-flavor-number scheme at next-to-leading order. Numerical results are compared to data where available, and uncertainties to scale variations, parton distribution functions and charm mass are discussed. I point out that measurements at large rapidity have the potential to pin down models of intrinsic charm.
The Large Hadron–Electron Collider at the HL-LHC
2021
The Large Hadron-Electron Collider (LHeC) is designed to move the field of deep inelastic scattering (DIS) to the energy and intensity frontier of particle physics. Exploiting energy-recovery technology, it collides a novel, intense electron beam with a proton or ion beam from the High-Luminosity Large Hadron Collider (HL-LHC). The accelerator and interaction region are designed for concurrent electron-proton and proton-proton operations. This report represents an update to the LHeC's conceptual design report (CDR), published in 2012. It comprises new results on the parton structure of the proton and heavier nuclei, QCD dynamics, and electroweak and top-quark physics. It is shown how the LH…
Heavy flavour production at the LHC: Theoretical Aspects
2008
CERN-DESY workshop on "HERA and the LHC" DESY-PROC-2009-02; ISBN 978-3-935702-32-4; ISSN 1435-8077; International audience; A proper inclusion of heavy quark mass effects in Parton Distribution Function fits has proved crucial. We present a review these effects in DIS and their impact on global analyses and lay out all elements of a properly defined general mass variable flavor number scheme (GM VFNS) that are shared by all modern formulations of the problem. We also report about progress in a number of theoretical problems related to exclusive measurements of heavy flavors. These topics include fragmentation functions for charmed mesons including finite mass effects, fragmentation function…
$\Lambda_c^{\pm}$ production in pp collisions with a new fragmentation function
2020
Physical review / D D 101(11), 114021 (2020). doi:10.1103/PhysRevD.101.114021
New Physics Constraints from Atomic Parity Violation in $^{133}$Cs
2021
Our improved calculation of the nuclear spin-independent parity violating electric dipole transition amplitude ($E1_{PV}$) for $6s ~ ^2S_{1/2} - 7s ~ ^2S_{1/2}$ in $^{133}$Cs in combination with the most accurate (0.3\%) measurement of this quantity yields a new value for the nuclear weak charge $Q_W=-73.71(26)_{ex} (23)_{th}$ against the Standard Model (SM) prediction $Q_W^{\text{SM}}=-73.23(1)$. The advances in our calculation of $E1_{PV}$ have been achieved by using a variant of the perturbed relativistic coupled-cluster theory which treats the contributions of the core, valence and excited states to $E1_{PV}$ on the same footing unlike the previous high precision calculations. Furthermo…
Study of heavy meson production in p-Pb collisions at $\sqrt{S}$=5.02 TeV in the general-mass variable-flavour-number scheme
2017
Nuclear physics / B 925, 415 - 430 (2017). doi:10.1016/j.nuclphysb.2017.10.016