41 research outputs found
Search for a narrow baryonic state decaying to and in deep inelastic scattering at HERA
A search for a narrow baryonic state in the and
system has been performed in collisions at HERA with the ZEUS detector
using an integrated luminosity of 358 pb taken in 2003-2007. The search
was performed with deep inelastic scattering events at an centre-of-mass
energy of 318 GeV for exchanged photon virtuality, , between 20 and 100
. Contrary to evidence presented for such a state around 1.52
GeV in a previous ZEUS analysis using a sample of 121 pb taken in
1996-2000, no resonance peak was found in the invariant-mass
distribution in the range 1.45-1.7 GeV. Upper limits on the production cross
section are set.Comment: 16 pages, 4 figures, accepted by Phys. Lett. B. Minor changes from
journal reviewing process, including a small correction to figure
Limits on the effective quark radius from inclusive scattering at HERA
The high-precision HERA data allows searches up to TeV scales for Beyond the
Standard Model contributions to electron-quark scattering. Combined
measurements of the inclusive deep inelastic cross sections in neutral and
charged current scattering corresponding to a luminosity of around 1
fb have been used in this analysis. A new approach to the beyond the
Standard Model analysis of the inclusive data is presented; simultaneous
fits of parton distribution functions together with contributions of "new
physics" processes were performed. Results are presented considering a finite
radius of quarks within the quark form-factor model. The resulting 95% C.L.
upper limit on the effective quark radius is cm.Comment: 10 pages, 4 figures, accepted by Phys. Lett.
Combined QCD and electroweak analysis of HERA data
A simultaneous fit of parton distribution functions (PDFs) and electroweak
parameters to HERA data on deep inelastic scattering is presented. The input
data are the neutral current and charged current inclusive cross sections which
were previously used in the QCD analysis leading to the HERAPDF2.0 PDFs. In
addition, the polarisation of the electron beam was taken into account for the
ZEUS data recorded between 2004 and 2007. Results on the vector and
axial-vector couplings of the Z boson to u- and d-type quarks, on the value of
the electroweak mixing angle and the mass of the W boson are presented. The
values obtained for the electroweak parameters are in agreement with Standard
Model predictions.Comment: 32 pages, 10 figures, accepted by Phys. Rev. D. Small corrections
from proofing process and small change to Fig. 12 and Table
Measurement of the cross-section ratio sigma_{psi(2S)}/sigma_{J/psi(1S)} in deep inelastic exclusive ep scattering at HERA
The exclusive deep inelastic electroproduction of and
at an centre-of-mass energy of 317 GeV has been studied with the ZEUS
detector at HERA in the kinematic range GeV,
GeV and GeV, where is the photon virtuality, is the
photon-proton centre-of-mass energy and is the squared four-momentum
transfer at the proton vertex. The data for GeV were taken in
the HERA I running period and correspond to an integrated luminosity of 114
pb. The data for GeV are from both HERA I and HERA II
periods and correspond to an integrated luminosity of 468 pb. The decay
modes analysed were and for the
and for the . The cross-section ratio
has been measured as a function of
and . The results are compared to predictions of QCD-inspired
models of exclusive vector-meson production.Comment: 24 pages, 8 figure
Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 2: The Physics Program for DUNE at LBNF
The Physics Program for the Deep Underground Neutrino Experiment (DUNE) at
the Fermilab Long-Baseline Neutrino Facility (LBNF) is described
Limits on contact interactions and leptoquarks at HERA
High-precision HERA data corresponding to a luminosity of around 1 fb have been used in the framework of contact interactions (CI) to set limits on possible high-energy contributions beyond the Standard Model to electron-quark scattering. Measurements of the inclusive deep inelastic cross sections in neutral and charged current scattering were considered. The analysis of the data has been based on simultaneous fits of parton distribution functions including contributions of CI couplings to scattering. Several general CI models and scenarios with heavy leptoquarks were considered. Improvements in the description of the inclusive HERA data were obtained for a few models. Since a statistically significant deviation from the Standard Model cannot be established, limits in the TeV range were set on all models considered
Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 1: The LBNF and DUNE Projects
This document presents the Conceptual Design Report (CDR) put forward by an international neutrino community to pursue the Deep Underground Neutrino Experiment at the Long-Baseline Neutrino Facility (LBNF/DUNE), a groundbreaking science experiment for long-baseline neutrino oscillation studies and for neutrino astrophysics and nucleon decay searches. The DUNE far detector will be a very large modular liquid argon time-projection chamber (LArTPC) located deep underground, coupled to the LBNF multi-megawatt wide-band neutrino beam. DUNE will also have a high-resolution and high-precision near detector
Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 2: The Physics Program for DUNE at LBNF
The Physics Program for the Deep Underground Neutrino Experiment (DUNE) at the Fermilab Long-Baseline Neutrino Facility (LBNF) is described