Determination of the strange quark content of the nucleon from a next-to-leading-order QCD analysis of neutrino charm production

Abstract We study charm production in charged-current deep-inelastic scattering (DIS) using the xFitter framework. Recent results from the LHC have focused renewed attention on the determination of the strange-quark parton distribution function (PDF), and the DIS charm process provides important complementary constraints on this quantity. We examine the current PDF uncertainty and use LHeC pseudodata to estimate the potential improvement from this proposed facility. As xFitter implements both fixed-flavor- and variable-flavor-number schemes, we can compare the impact of these different theoretical choices; this highlights some interesting aspects of multi-scale calculations. We find that the high-statistics LHeC data covering a wide kinematic range could substantially reduce the strange PDF uncertainty.

Download Full-text

Determination of the Strange Quark Content of the Proton

Associated Production of W + Charm in 13 TeV Proton-Proton Collisions Measured with CMS and Determination of the Strange Quark Content of the Proton - Springer Theses ◽

10.1007/978-3-030-52762-4_6 ◽

2020 ◽

pp. 99-108

Author(s):

Svenja Karen Pflitsch

Keyword(s):

Strange Quark ◽

Quark Content

Download Full-text

Associated Production of W + Charm in 13 TeV Proton-Proton Collisions Measured with CMS and Determination of the Strange Quark Content of the Proton

10.1007/978-3-030-52762-4 ◽

2020 ◽

Author(s):

Svenja Karen Pflitsch

Keyword(s):

Strange Quark ◽

Proton Proton ◽

Proton Collisions ◽

Associated Production ◽

Proton Proton Collisions ◽

Quark Content

Download Full-text

NLO QCD ANALYSIS OF POLARIZED DEEP INELASTIC SCATTERING

International Journal of Modern Physics A ◽

10.1142/s0217751x98002547 ◽

1998 ◽

Vol 13 (32) ◽

pp. 5573-5592 ◽

Cited By ~ 58

Author(s):

ELLIOT LEADER ◽

ALEKSANDER V. SIDOROV ◽

DIMITER B. STAMENOV

Keyword(s):

Experimental Data ◽

Inelastic Scattering ◽

Smooth Function ◽

Gluon Density ◽

Precise Determination ◽

Leading Order ◽

Counting Rules ◽

Qcd Analysis ◽

Polarized Deep Inelastic Scattering

We have carried out a next-to-leading order QCD analysis of the experimental data on polarized DIS in the [Formula: see text] scheme. We have studied two models of the parametrizations of the input parton densities — the first due to Brodsky, Burkhardt and Schmidt (BBS), which gives a simultaneous parametrization for the polarized and unpolarized densities and in which the counting rules are strictly imposed; in the second, the input polarized densities are written in terms of the unpolarized ones in the generic form Δq(x)=f(x)q(x), with f(x) some simple smooth function. In both cases a good fit to the polarized data is achieved. As expected, the polarized data do not allow a precise determination of the polarized gluon density. Concerning the polarized sea quark densities, these are fairly well determined in the BBS model because of the interplay of polarized and unpolarized data, whereas in the second model, where only the polarized data are relevant, the polarized sea quark densities are largely undetermined.

Download Full-text

Constraints on neutrino non-standard interactions from LHC data with large missing transverse momentum

Journal of High Energy Physics ◽

10.1007/jhep02(2021)033 ◽

2021 ◽

Vol 2021 (2) ◽

Author(s):

DianYu Liu ◽

ChuanLe Sun ◽

Jun Gao

Keyword(s):

Transverse Momentum ◽

Neutral Current ◽

Data Sets ◽

Leading Order ◽

Missing Transverse Momentum ◽

Upper Limit ◽

Theoretical Predictions ◽

Parton Showering ◽

Single Jet

Abstract The possible non-standard interactions (NSIs) of neutrinos with matter plays important role in the global determination of neutrino properties. In our study we select various data sets from LHC measurements at 13 TeV with integrated luminosities of 35 ∼ 139 fb−1, including production of a single jet, photon, W/Z boson, or charged lepton accompanied with large missing transverse momentum. We derive constraints on neutral-current NSIs with quarks imposed by different data sets in a framework of either effective operators or simplified Z′ models. We use theoretical predictions of productions induced by NSIs at next-to-leading order in QCD matched with parton showering which stabilize the theory predictions and result in more robust constraints. In a simplified Z′ model we obtain a 95% CLs upper limit on the conventional NSI strength ϵ of 0.042 and 0.0028 for a Z′ mass of 0.2 and 2 TeV respectively. We also discuss possible improvements from future runs of LHC with higher luminosities.

Download Full-text

Bs → Kℓv form factors with 2+1 flavors

EPJ Web of Conferences ◽

10.1051/epjconf/201817513008 ◽

2018 ◽

Vol 175 ◽

pp. 13008 ◽

Cited By ~ 2

Author(s):

Yuzhi Liu ◽

Jon A. Bailey ◽

A. Bazavov ◽

C. Bernard ◽

C. M. Bouchard ◽

...

Keyword(s):

Quark Mass ◽

Strange Quark ◽

Lattice Spacing ◽

Light Quark ◽

Form Factors ◽

Ckm Matrix ◽

Strange Quark Mass ◽

Light Quark Mass ◽

B Quark

Using the MILC 2+1 flavor asqtad quark action ensembles, we are calculating the form factors f0 and f+ for the semileptonic Bs → Kℓv decay. A total of six ensembles with lattice spacing from ≈ 0.12 to 0.06 fm are being used. At the coarsest and finest lattice spacings, the light quark mass m’l is one-tenth the strange quark mass m’s. At the intermediate lattice spacing, the ratio m’l/m’s ranges from 0.05 to 0.2. The valence b quark is treated using the Sheikholeslami-Wohlert Wilson-clover action with the Fermilab interpretation. The other valence quarks use the asqtad action. When combined with (future) measurements from the LHCb and Belle II experiments, these calculations will provide an alternate determination of the CKM matrix element |Vub|.

Download Full-text