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Stratmann, Marco

Publications and source records attributed to Stratmann, Marco.

7 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Eta Fragmentation Functions Revisited

We revisit the extraction of parton-to-eta meson fragmentation functions at next-to-leading order accuracy in QCD in the light of the recent hadroproduction measurements in proton-proton collisions obtained by the PHENIX, LHCb, and ALICE collaborations. In addition to an increased precision, the data explore complementary rapidity ranges and center-of-mass system energies. The analysis exploits the theoretical scale dependence to ease tensions among the data sets at different energies that are potentially caused by QCD corrections beyond the next-to-leading order. The resulting set of fragmentation functions yields a consistent description of all available data. Estimates of uncertainties are obtained with the Monte Carlo replica method.

FOS: Physical sciences↗
DOE OSTI2017

Open Charm Production and Nuclear Gluon Densities

Open Charm Production and Nuclear Gluon Densities Very little is known about nuclear gluon densities. We explore the direct measurements of nuclear gluon densities via open charm and beauty production at an Electron-Ion Collider (EIC). In the high-x ranges x ~ 0.05-0.15 (antishadowing) and x>0.3 (EMC effect) strong modifications are expected relative to the incoherent sum of nucleon gluon distributions. These effects offer insight into non-nucleonic degrees of freedom and the QCD structure of nucleon-nucleon interactions. We describe the charm production rates in nuclear deep-inelastic scattering (DIS) at large x_B, and comment on methods for charm reconstruction using next-generation detectors at the EIC (pi/K identification, tracking, vertex detection). Presenter : Prof. HYDE, Charles (Old Dominion University)

Hyde, Charles↗
DOE OSTI2017

Pre-Town Meeting on spin physics at an Electron-Ion Collider

A polarized ep/eA collider (Electron-Ion Collider, or EIC), with polarized proton and light-ion beams and unpolarized heavy-ion beams with a variable center-of-mass energy √s ~ 20 to ~ 100 GeV (upgradable to ~ 150 GeV) and a luminosity up to ~10 34 cm -2 s -1 , would be uniquely suited to address several outstanding questions of Quantum Chromodynamics, and thereby lead to new qualitative and quantitative information on the microscopic structure of hadrons and nuclei. During this meeting at Jefferson Lab we addressed recent theoretical and experimental developments in the spin and the three-dimensional structure of the nucleon (sea quark and gluon spatial distributions, orbital motion, polarization, and their correlations). Finally, this mini-paper contains a short update on progress in these areas since the EIC White paper (A. Accardi et al., Eur. Phys. J. A 52, 268 (2016)).

43 PARTICLE ACCELERATORS↗
DOE OSTI2017

Fragmentation functions beyond fixed order accuracy

Here, we give a detailed account of the phenomenology of all-order resummations of logarithmically enhanced contributions at small momentum fraction of the observed hadron in semi-inclusive electron-positron annihilation and the timelike scale evolution of parton-to-hadron fragmentation functions. The formalism to perform resummations in Mellin moment space is briefly reviewed, and all relevant expressions up to next-to-next-to-leading logarithmic order are derived, including their explicit dependence on the factorization and renormalization scales. We discuss the details pertinent to a proper numerical implementation of the resummed results comprising an iterative solution to the timelike evolution equations, the matching to known fixed-order expressions, and the choice of the contour in the Mellin inverse transformation. First extractions of parton-to-pion fragmentation functions from semi-inclusive annihilation data are performed at different logarithmic orders of the resummations in order to estimate their phenomenological relevance. To this end, we compare our results to corresponding fits up to fixed, next-to-next-to-leading order accuracy and study the residual dependence on the factorization scale in each case.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2016

Probing nuclear gluons with heavy flavors at an Electron-Ion Collider

We explore the feasibility of direct measurements of nuclear gluon densities using heavy-quark production (open charm, beauty) at a future Electron-Ion Collider (EIC). We focus on the regions x > 0.3 (EMC effect) and x ~ 0.05 -0.1 (antishadowing), where the nuclear modifications of the gluon density offer insight into non-nucleonic degrees of freedom and the QCD structure of nucleon-nucleon interactions. We describe the charm production rates and momentum distributions in nuclear deep-inelastic scattering (DIS) at large x_B, and comment on the possible methods for charm reconstruction using next-generation detectors at the EIC (pi/K identification, tracking, vertex detection).

Chudakov, Eugene↗
DOE OSTI2016

Nuclear gluons with charm at a future EIC

A future Electron-Ion Collider would enable the first direct measurements of nuclear gluon densities at large x using heavy-quark production (open charm and beauty). We summarize the motivation for such measurements and report about process simulations carried out under JLab LDRD project LD1601 "Nuclear gluons with charm at EIC."

Nguyen, Dien↗