New parton distributions for collider physics

Abstract. We present APFEL Web, a Web-based application designed to provide a flexible user-friendly tool for the graphical visualization of parton distribution functions (PDFs). In this note we describe the technical design of the APFEL Web application, motivating the choices and the framework used for the development of this project. We document the basic usage of APFEL Web and show how it can be used to provide useful input for a variety of collider phenomenological studies. Finally we provide some examples showing the output generated by the application.

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“…The bottom-left image of Fig. 3 shows the comparison between NNPDF2.3 NLO [4], CT10 NLO [13] and MSTW2008 NLO [14] sets at Q = 1 GeV.…”

Section: Resultsmentioning

confidence: 99%

APFEL Web: a web-based application for the graphical visualization of parton distribution functions

Carrazza

Ferrara

Palazzo

et al. 2015

J. Phys. G: Nucl. Part. Phys.

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“…Taking advantage of the fact that PDF and fragmentation functions are independent of the partonic process, The PDF currently cannot be calculated from first principles, and is therefore obtained through parametrizations of experimental data. There are multiple publically available PDF sets, such as those from the CTEQ [80,81] and NNPDF [82] collaborations. The MC simulation samples described in this thesis all employ the CTEQ6L1 PDF set.…”

Section: Monte-carlo Event Generatorsmentioning

confidence: 99%

Search for Supersymmetry in pp Collisions at √s = 8 TeV with a Photon, Lepton, and Missing Transverse Energy

Iiyama¹

2017

Springer Theses

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This thesis presents a search for anomalous production of events with at least one photon, one electron or muon, and large missing transverse energy in proton-proton collisions at a center-of-mass energy of 8 TeV. A data set corresponding to an integrated luminosity of 19.7 fb −1 recorded in 2012 by the Compact Muon Solenoid detector at the CERN Large Hadron Collider is analyzed. The search is motivated by a class of supersymmetric extensions of the standard model with gauge-mediated supersymmetry breaking, which predicts decays of supersymmetric particles into a W boson, a photon, and highly energetic gravitinos, which are undetected and lead to a momentum imbalance in the plane transverse to the proton beams. The expected standard model background contributions of events featuring the same final state signature is estimated by separating the background processes into categories and applying estimation techniques tailored for each category. No excess of events with large missing transverse energy is observed beyond the expectations from standard model processes. The result of this search is interpreted as 95% confidence level upper limits on the production cross section of supersymmetric particles as well as generic new-physics particles in two simplified models. The cross section upper limits set by this search pose the most stringent constraint to date on the considered supersymmetric models.

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“…To correct for possible differences between data and simulation, a datadriven method similar to the one described in [11] is used to determine correction factors to the baseline lepton efficiencies from simulation. The Z boson measurement is additionally corrected for acceptance that is calculated using the POWHEG generator [15] with CT10NLO free proton PDF set [16] and interfaced with PYTHIA parton shower. …”

Section: Analysis Proceduresmentioning

confidence: 99%

Z and W boson production in pPb collisions with CMS

Zsigmond

2014

Nuclear Physics A

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The electroweak boson production is an important benchmark measurement in ultra-relativistic heavyion collisions which can provide constraints on the nuclear parton distribution functions. In this paper the first results from the proton-lead collision data taken in early 2013 are presented. The Z boson production cross section is measured in the muon decay channel in bins of transverse momentum and rapidity together with the forward-backward ratio. The W production is studied in the muon and electron decay channels and the differential cross sections, lepton-charge and forward-backward asymmetries are computed as a function of the lepton pseudorapidity. All results are compared with theory predictions with and without nuclear modification of the parton distribution functions showing hints of nuclear effects. Presented at QM2014 Quark Matter 2014Nuclear Physics A 00 (2014) AbstractThe electroweak boson production is an important benchmark measurement in ultra-relativistic heavy-ion collisions which can provide constraints on the nuclear parton distribution functions. In this paper the first results from the proton-lead collision data taken in early 2013 are presented. The Z boson production cross section is measured in the muon decay channel in bins of transverse momentum and rapidity together with the forward-backward ratio. The W production is studied in the muon and electron decay channels and the differential cross sections, lepton-charge and forward-backward asymmetries are computed as a function of the lepton pseudorapidity. All results are compared with theory predictions with and without nuclear modification of the parton distribution functions showing hints of nuclear effects.

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New parton distributions for collider physics

Cited by 1,815 publications

References 64 publications

APFEL Web: a web-based application for the graphical visualization of parton distribution functions

APFEL Web: a web-based application for the graphical visualization of parton distribution functions

Search for Supersymmetry in pp Collisions at √s = 8 TeV with a Photon, Lepton, and Missing Transverse Energy

Z and W boson production in pPb collisions with CMS

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