79 research outputs found
QCD FITS TO NEUTRINO-IRON STRUCTURE FUNCTIONS AT NUTEV
This thesis presents a new determination of from Next-to-Leading Order QCD fits to the dependence of neutrino-ironstructure functions. This is the first measurement of which uses a theoretical model that fully accounts for heavy quark production.Compared with previous neutrino measurements,the result has improved understandingof the largest systematic uncertainties onthe muon and hadron energy scales. These improvements lead to one of the most precise determination of atmoderate .NuTeV is a neutrino-iron deep inelastic scattering (DIS) experiment that collected data during 1996-97 at Fermilab. The key features of NuTeV include its sign-selected beam whichproduced separate high purity neutrino andantineutrino beams, and its continuous calibration beam which enabled NuTeV to considerably improve the knowledge of energy scales whichhave dominated uncertainties in the previousmeasurements
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QCD fits to neutrino-iron structure functions at NuTeV
This thesis presents a new determination of {Lambda}{sub QCD} from Next-to-Leading Order QCD fits to the Q{sup 2} dependence of neutrino-iron structure functions. This is the first measurement of {Lambda}{sub QCD} which uses a theoretical model that fully accounts for heavy quark production. Compared with previous neutrino measurements, the result has improved understanding of the largest systematic uncertainties on the muon and hadron energy scales. These improvements lead to one of the most precise determination of {alpha}{sub S} at moderate Q{sup 2}. NuTeV is a neutrino-iron deep inelastic scattering (DIS) experiment that collected data during 1996-97 at Fermilab. The key features of NuTeV include its sign-selected beam which produced separate high purity neutrino and antineutrino beams, and its continuous calibration beam which enabled NuTeV to considerably improve the knowledge of energy scales which have dominated uncertainties in the previous measurements
A determination of mc(mc) from HERA data using a matched heavy-flavor scheme
The charm quark mass is one of the fundamental parameters of the Standard
Model Lagrangian. In this work we present a determination of the MSbar charm
mass from a fit to the inclusive and charm HERA deep-inelastic structure
function data. The analysis is performed within the xFitter framework, with
structure functions computed in the FONLL general-mass scheme as implemented in
APFEL. In the case of the FONLL-C scheme, we obtain mc(mc) = 1.335 +-
0.043(exp) +0.019 -0.000(param) +0.011 -0.008(mod) +0.033 -0.008(th) GeV. We
also perform an analogous determination in the fixed-flavor-number scheme at
next-to-leading order, finding mc(mc) = 1.318 +- 0.054(exp) +0.011
-0.010(param) +0.015 -0.019(mod) +0.045 -0.004(th) GeV, compatible with the
FONLL-C value. Our results are consistent with previous determinations from DIS
data as well as with the PDG world average.Comment: 37 pages, 12 figures, 3 table
A Review of Target Mass Corrections
With recent advances in the precision of inclusive lepton--nuclear scattering
experiments, it has become apparent that comparable improvements are needed in
the accuracy of the theoretical analysis tools. In particular, when extracting
parton distribution functions in the large-x region, it is crucial to correct
the data for effects associated with the nonzero mass of the target. We present
here a comprehensive review of these target mass corrections (TMC) to structure
functions data, summarizing the relevant formulas for TMCs in electromagnetic
and weak processes. We include a full analysis of both hadronic and partonic
masses, and trace how these effects appear in the operator product expansion
and the factorized parton model formalism, as well as their limitations when
applied to data in the x->1 limit. We evaluate the numerical effects of TMCs on
various structure functions, and compare fits to data with and without these
corrections.Comment: 41 pages, 13 figures; minor updates to match published versio
The PDF4LHC report on PDFs and LHC data: Results from Run I and preparation for Run II
The accurate determination of the Parton Distribution Functions (PDFs) of the
proton is an essential ingredient of the Large Hadron Collider (LHC) program.
PDF uncertainties impact a wide range of processes, from Higgs boson
characterisation and precision Standard Model measurements to New Physics
searches. A major recent development in modern PDF analyses has been to exploit
the wealth of new information contained in precision measurements from the LHC
Run I, as well as progress in tools and methods to include these data in PDF
fits. In this report we summarise the information that PDF-sensitive
measurements at the LHC have provided so far, and review the prospects for
further constraining PDFs with data from the recently started Run II. This
document aims to provide useful input to the LHC collaborations to prioritise
their PDF-sensitive measurements at Run II, as well as a comprehensive
reference for the PDF-fitting collaborations.Comment: 55 pages, 13 figure
PDF4LHC recommendations for LHC Run II
We provide an updated recommendation for the usage of sets of partondistribution functions (PDFs) and the assessment of PDF and PDF+uncertainties suitable for applications at the LHC Run II. We reviewdevelopments since the previous PDF4LHC recommendation, and discuss and comparethe new generation of PDFs, which include substantial information fromexperimental data from the Run I of the LHC. We then propose a new prescriptionfor the combination of a suitable subset of the available PDF sets, which ispresented in terms of a single combined PDF set. We finally discuss tools whichallow for the delivery of this combined set in terms of optimized sets ofHessian eigenvectors or Monte Carlo replicas, and their usage, and provide someexamples of their application to LHC phenomenology
Les Houches 2013: Physics at TeV Colliders: Standard Model Working Group Report
This Report summarizes the proceedings of the 2013 Les Houches workshop on
Physics at TeV Colliders. Session 1 dealt primarily with (1) the techniques for
calculating standard model multi-leg NLO and NNLO QCD and NLO EW cross sections
and (2) the comparison of those cross sections with LHC data from Run 1, and
projections for future measurements in Run 2.Comment: Proceedings of the Standard Model Working Group of the 2013 Les
Houches Workshop, Physics at TeV Colliders, Les houches 3-21 June 2013. 200
page
Quantum Computing for High-Energy Physics: State of the Art and Challenges. Summary of the QC4HEP Working Group
Quantum computers offer an intriguing path for a paradigmatic change of
computing in the natural sciences and beyond, with the potential for achieving
a so-called quantum advantage, namely a significant (in some cases exponential)
speed-up of numerical simulations. The rapid development of hardware devices
with various realizations of qubits enables the execution of small scale but
representative applications on quantum computers. In particular, the
high-energy physics community plays a pivotal role in accessing the power of
quantum computing, since the field is a driving source for challenging
computational problems. This concerns, on the theoretical side, the exploration
of models which are very hard or even impossible to address with classical
techniques and, on the experimental side, the enormous data challenge of newly
emerging experiments, such as the upgrade of the Large Hadron Collider. In this
roadmap paper, led by CERN, DESY and IBM, we provide the status of high-energy
physics quantum computations and give examples for theoretical and experimental
target benchmark applications, which can be addressed in the near future.
Having the IBM 100 x 100 challenge in mind, where possible, we also provide
resource estimates for the examples given using error mitigated quantum
computing
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