High-precision HERA data corresponding to a luminosity of around 1 fb-1 have been used in the framework of eeqq 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 ep scattering were considered. The analysis of the ep data has been based on simultaneous fits of parton distribution functions including contributions of CI couplings to ep 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.
High-precision HERA data corresponding to a luminosity of around 1 fb$^{-1}$ have been used in the framework of eeqq 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 ep scattering were considered. The analysis of the ep data has been based on simultaneous fits of parton distribution functions including contributions of CI couplings to ep 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.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) Abstract The photoproduction of D ^sup ±^ mesons has been measured with the ZEUS detector at HERA at three different ep ...centre-of-mass energies, ..., of 318, 251 and 225 GeV. For each data set, D ^sup ±^ mesons were required to have transverse momentum, p ^sub T^^sup D^, and pseudo-rapidity, eta ^sup D^, in the ranges 1.9 < p ^sub T^^sup D^ < 20 GeV and |eta ^sup D^| < 1.6. The events were required to have a virtuality of the incoming photon, Q ^sup 2^, of less than 1 GeV^sup 2^. The dependence on ... was studied by normalising to the high-statistics measurement at ... GeV. This led to the cancellation of a number of systematic effects both in data and theory. Predictions from next-to-leading-order QCD describe the ... dependence of the data well.
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 \(ep\) scattering corresponding to a luminosity of around 1 fb\(^{-1}\) have been used in this analysis. A new approach to the beyond the Standard Model analysis of the inclusive \(ep\) 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 \(0.43\cdot 10^{-16}\) cm.
Dijet differential cross sections for the reaction e+p→e++jet+jet+X in the photoproduction regime have been measured with the ZEUS detector at HERA using an integrated luminosity of 42.7 pb−1. The ...cross sections are given for photon–proton centre-of-mass energies in the range 134<W<277 GeV. The differential cross sections as a function of the dijet mass, Mjj, and of the dijet angular variables have been measured for 47<Mjj<160 GeV and compared to next-to-leading-order QCD calculations. The dijet events in the region 75<Mjj<100 GeV have been used to derive a 95% C.L. upper limit on the cross section for Z0 photoproduction of σe+p→e+Z0X<5.9 pb. Upper limits on the photoproduction of new heavy resonances decaying into two jets are also presented for masses in the range between 60 GeV and 155 GeV.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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.
Phys. Lett. B 759 (2016) 446-453 A search for a narrow baryonic state in the $pK^0_S$ and $\bar{p}K^0_S$
system has been performed in $ep$ collisions at HERA with the ZEUS detector
using an ...integrated luminosity of 358 pb$^{-1}$ taken in 2003-2007. The search
was performed with deep inelastic scattering events at an $ep$ centre-of-mass
energy of 318 GeV for exchanged photon virtuality, $Q^2$, between 20 and 100
$\rm{} GeV^{2}$. Contrary to evidence presented for such a state around 1.52
GeV in a previous ZEUS analysis using a sample of 121 pb$^{-1}$ taken in
1996-2000, no resonance peak was found in the $p(\bar{p})K^0_S$ invariant-mass
distribution in the range 1.45-1.7 GeV. Upper limits on the production cross
section are set.
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