Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userA Study of the PDF uncertainty on the LHC W-boson mass measurement
81
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
The determination of the $W$-boson mass through an analysis of the decay charged-lepton transverse momentum distribution has a sizable uncertainty due to the imperfect knowledge of the relevant parton distribution functions (PDFs). In this paper, a quantitative assessment of the $W$-boson mass uncertainty at the LHC resulting from the PDF uncertainty is examined. We use the CT14 NNLO PDFs with a NNLL + NNLO calculation (ResBos) to simulate the $W$-boson production and decay kinematics. The uncertainty of the $W$-boson mass determination is then determined as a function of the boson and lepton kinematics. For $W^{+}$ production using $P_{T}^{W} < 15$ GeV and $35 < P_{T}^{l}$ (GeV) $< 45$, PDF uncertainties (at the 68% CL) of $^{+16.0}_{-17.5}$ MeV, $^{+13.9}_{-14.8}$ MeV, and $^{+12.2}_{-19.2}$ MeV, are determined at 7 TeV, 8 TeV and 13 TeV respectively. The uncertainties of $W^{-}$ for the same cuts are found to be $^{+15.9}_{-15.6}$ MeV, $^{+15.0}_{-12.7}$ MeV and $^{+14.8}_{-15.3}$ MeV, at 7 TeV, 8 TeV and 13 TeV respectively.
rate research
Read More
We present the currently most precise W boson mass (M_W) prediction in the Minimal Supersymmetric Standard Model (MSSM) and discuss how it is affected by recent results from the LHC. The evaluation includes the full one-loop result and all known higher order corrections of SM and SUSY type. We show the MSSM prediction in the M_W-m_t plane, taking into account constraints from Higgs and SUSY searches. We point out that even if stops and sbottoms are heavy, relatively large SUSY contributions to M_W are possible if either charginos, neutralinos or sleptons are light. In particular we analyze the effect on the M_W prediction of the Higgs signal at about 125.6 GeV, which within the MSSM can in principle be interpreted as the light or the heavy CP-even Higgs boson. For both interpretations the predicted MSSM region for M_W is in good agreement with the experimental measurement. We furthermore discuss the impact of possible future LHC results in the stop sector on the M_W prediction, considering both the cases of improved limits and of the detection of a scalar top quark.
The $W$ boson mass is measured using proton-proton collision data at $sqrt{s}=13$ TeV corresponding to an integrated luminosity of 1.7 fb$^{-1}$ recorded during 2016 by the LHCb experiment. With a simultaneous fit of the muon $q/p_T$ distribution of a sample of $W to mu u$ decays and the $phi^*$ distribution of a sample of $Ztomumu$ decays the $W$ boson mass is determined to be begin{equation*} m_{W} = 80354 pm 23_{rm stat} pm 10_{rm exp} pm 17_{rm theory} pm 9_{rm PDF}~mathrm{MeV}, end{equation*} where uncertainties correspond to contributions from statistical, experimental systematic, theoretical and parton distribution function sources. This is an average of results based on three recent global parton distribution function sets. The measurement agrees well with the prediction of the global electroweak fit and with previous measurements.
We present a renormalizable theory that includes a $W$ boson of mass in the 1.8-2 TeV range, which may explain the excess events reported by the ATLAS Collaboration in a $WZ$ final state, and by the CMS Collaboration in $e^+!e^- jj$, $Wh^0$ and $jj$ final states. The $W$ boson couples to right-handed quarks and leptons, including Dirac neutrinos with TeV-scale masses. This theory predicts a $Z$ boson of mass in the 3.4-4.5 TeV range. The cross section times branching fractions for the narrow $Z$ dijet and dilepton peaks at the 13 TeV LHC are 10 fb and 0.6 fb, respectively, for $M_{Z}= 3.4$ TeV, and an order of magnitude smaller for $M_{Z}= 4.5$ TeV.
We investigate the impact of parton distribution functions (PDFs) uncertainties on W/Z production at the LHC, concentrating on the strange quark PDF. Additionally we examine the extent to which precise measurements at the LHC can provide additional information on the proton flavor structure.
Within the framework of transverse-momentum-dependent factorization, we investigate for the first time the impact of a flavor-dependent intrinsic transverse momentum of quarks on the production of $W^{pm}$ bosons in proton-proton collisions at $sqrt{s}$ = 7 TeV. We estimate the shift in the extracted value of the $W$ boson mass $M_W$ induced by different choices of flavor-dependent parameters for the intrinsic quark transverse momentum by means of a template fit to the transverse-mass and the lepton transverse-momentum distributions of the $W$-decay products. We obtain $-6leq Delta M_{W^+} leq 9$ MeV and $-4leq Delta M_{W^-} leq 3$ MeV with a statistical uncertainty of $pm 2.5$ MeV. Our findings call for more detailed investigations of flavor-dependent nonperturbative effects linked to the proton structure at hadron colliders.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
