8,083 research outputs found

### Electroweak precision measurements with the CMS detector

We report on a precision measurement of the effective weak mixing angle using
the forward-backward asymmetry of Drell-Yan ($ee$ and $\mu\mu$) events in pp
collisions at $\sqrt{s}=8~\mathrm{TeV}$ at CMS. The data sample corresponds to
an integrated luminosity of $18.8~\mathrm{fb}^{-1}$ and $19.6~\mathrm{fb}^{-1}$
for muon and electron channels, respectively. The sample consists of 8.2
million dimuon and 4.9 million dielectron events. With new analysis techniques
and large samples the statistical and systematic uncertainties are reduced by a
factor of two compared to previous measurements at the LHC. The extracted value
of the effective weak mixing angle from the combined $ee$ and $\mu\mu$ data
samples is $sin^2\theta^{lept}_{eff}=0.23101\pm 0.00036(stat)\pm
0.00018(syst)\pm 0.00016(theory)\pm 0.00030(pdf)$ or $sin^2\theta^{lept}_{eff}=0.23101\pm0.00052$.Comment: 6 pages 2 figures. To be published in Proceeding of EPS 2017, Lido,
Ital

### Standard Model Precision Electroweak Measurements at HL-LHC and Future Hadron Colliders

We investigate the uncertainties for current and future measurements of
electroweak (EW) parameters at hadron colliders. These include the measurement
of the mass of the top quark ($M_T$), the direct measurement of the mass of the
W boson ($M_W^{direct}$), the measurement of the effective EW mixing angle
$\sin^2\theta^{\rm lept}_{\rm eff}$(M$_Z$), and the measurement of the on-shell
EW mixing angle $\sin^2\theta_{W}= 1- M_W^2/M_Z^2$ which is equivalent to an
indirect measurement of the W mass ($M_W^{indirect}$). Reduction of a factor of
2 to 3 in the measurement errors is expected in the future.Comment: Talk presented CIPANP2015. 13 pages, LaTeX, 5 pdf figures,, 3 Table

### Studies of Higher Twist and Higher Order Effects in NLO and NNLO QCD Analysis of Lepton-Nucleon Scattering Data on F_2 and R =sigma_L/sigma_T

We report on the extraction of the higher twist contributions to F_2 and R =
sigma_L/sigma_T from the global NLO and NNLO QCD fits to lepton nucleon
scattering data over a wide range of Q^2. The NLO fits require both target mass
and higher twist contributions at low Q^2. However, in the NNLO analysis, the
data are described by the NNLO QCD predictions (with target mass corrections)
without the need for any significant contributions from higher twist effects.
An estimate of the difference between NLO and NNLO parton distribution
functions is obtained.Comment: 5 pages, 6 figures, submitted to Eur. Phys.

### Modeling Neutrino and Electron Scattering Cross Sections in the Few GeV Region with Effective $LO PDFs$

We use new scaling variables $x_w$ and $\xi_w$, and add low $Q^2$
modifications to GRV94 and GRV98 leading order parton distribution functions
such that they can be used to model electron, muon and neutrino inelastic
scattering cross sections (and also photoproduction) at both very low and high
energie.Comment: 8 pages, 3 figures, Invited talk given by Arie Bodek at the X Mexican
School of Particles and Fields, Playa del Carmen, Mexico, 200

### Modeling Neutrino Quasielastic Cross Sections on Nucleons and Nuclei

We calculate the total and differential quasielastic cross sections for
neutrino and antineutrino scattering on nucleons using up to date fits to the
nucleon elastic electromagnetic form factors $G_E^p$, $G_E^n$, $G_M^p$,
$G_M^n$, and $F_A$ and pseudoscalar form factors. We compare predictions of the
cross sections for nucelons and nuclei to experimental data.Comment: 5 pages, 4 figures, Presented by Arie Bodek at CIPANP2003, New York
City, NY 2003 - to be published in proceeding

### Extraction of the Axial Nucleon Form Factor from Neutrino Experiments on Deuterium

We present new parameterizations of vector and axial nucleon form factors. We
maintain an excellent descriptions of the form factors at low momentum
transfers ($Q^2$), where the spatial structure of the nucleon is important, and
use the Nachtman scaling variable $\xi$ to relate elastic and inelastic form
factors and impose quark-hadron duality constraints at high $Q^2$ where the
quark structure dominates. We use the new vector form factors to re-extract
updated values of the axial form factor from \numu experiments on deuterium.
We obtain an updated world average value from \numud, \numubarH and pion
electroproduction experiments of $M_{A}$ = $1.014 \pm 0.014 GeV/c^2$. Our
parameterizations are useful in modeling $\nu$ interactions at low energies
(e.g. for \numu oscillations experiments). The predictions for high $Q^2$ can
be tested in the next generation electron and \numu scattering experiments.Comment: Presented by A. Bodek at the European Physical Society Meeting,
EPS2007, Manchester, England, July 2007, 4 pages, 2 figure

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