244 Works

Exclusive Dimuon production at LHCb.

Dermot Moran
We report on preliminary results for the measurement of exclusive dimuon production at LHCb. Cross-section measurements for exclusive $J/\psi$, $\psi\prime$ and for non-resonant production $p+p\rightarrow p+ \mu^+ \mu^- +p$ are presented and comparisons made with theory. The additional requirement of a single photon allows the the cross-section for exclusive $\chi_c$ production to be measured and also the relative contribution of $\chi_c^0$,$\chi_c^1$,$\chi_c^2$ to be determined.

Searches for Standard Model Higgs boson at CMS.

Pietro Govoni
A search for the Standard Model Higgs boson has been performed by the CMS Collaboration, with the full dataset delivered by the LHC during the 2011, in a wide spectrum of channels. The statistical combination of the results allows to exclude a wide region of its mass at 95\% confidence level: 127.5 -- 600~GeV/c$^2$. A modest excess at about 125~GeV/c$^2$ is observed, with a significance of 1.6~$\sigma$ in the range 110 -- 150~GeV/c$^2$. More data...

Status of polarized structure functions.

Claude Marchand
An experimental overview on polarized structure functions of the nucleon is given. It covers results from experiments performed at CERN, HERA, JLAB and RHIC. Latest results on quark and gluon helicities are discussed, as well as results on Transverse Momentum Dependent distribution functions (TMD).

The ALICE Upgrade Program.

Thomas Peitzmann
While groundbreaking measurements on the properties of strongly interacting matter in p+p, p+A and A+A collisions at the LHC are being performed, it is clear that many important questions in heavy-ion physics will remain unanswered in this first phase of beam times up to 2017. The ALICE is setting up a program of detector upgrades to be installed in the LHC shutdown planned for 2017/18, to address the new scientific challenges. We will discuss examples...

From Jet Counting to Jet Vetoes.

Peter Schichtel, Christoph Englert, Erik Gerwick, Tilman Plehn & Steffen Schumann
The properties of multi-jet events impact many LHC analysis. The exclusive number of jets at hadron colliders can be described in terms of two simple patterns: staircase scaling and Poisson scaling. In photon plus jets production we can interpolate between the two patterns using simple kinematic cuts. The associated theoretical errors are well under control. Understanding such exclusive jet multiplicities significantly impacts Higgs searches and searches for supersymmetry at the LHC.

Measurements of Jets containing Charm and Bottom Quarks with the ATLAS Detector.

David Calvet
The inclusive and dijet production cross-sections have been measured for jets containing $b$-hadrons ($b$-jets) in proton-proton collisions at the LHC using the ATLAS detector. The $b$-jets are identified using either a lifetime-based method or a muon-based method. $D^{*\pm}$ meson production in jets is also measured, with fully reconstructed $D^{*\pm}$ mesons. The results are compared to next-to-leading-order QCD predictions.

European XFEL Annual Report 2011

Massimo Altarelli

Hard Exclusive $\phi$ meson leptoproduction at HERMES.

Mayya Golembiovskaya, Armine Rostomyan, Sergey Yaschenko & Denis Veretennikov
AThe HERMES experiment at DESY, Hamburg collected a set of data on hard exclusive vector meson ($\rho^{0}$, $\phi$ , $\omega$) leptoproduction using the 27.6 GeV self-polarized lepton beam of HERA accelerator and a longitudinally or transversely polarized or unpolarized gas target. The latest results for spin density matrix elements of exclusive $\phi$ meson production using the full statistics collected at HERMES are presented. Conclusions on the helicity amplitudes, which are related to spin density matrix...

Production of $c \bar c$ pairs at LHC: $k_t$-factorization and double-parton scattering.

Antoni Szczurek
We discuss charm production at LHC. The production of single $c \bar c$ pairs is calculated in the $k_t$-factorization approach. We use several unintegrated gluon distributions from the literature. Differential distributions for several charmed mesons are presented and compared to recent results of the ALICE and LHCb collaborations. Some missing strength can be observed. Furthermore we discuss production of two $c \bar c$ pairs within a simple formalism of double-parton scattering (DPS). Surprisingly large cross...

Precision QCD and electroweak physics at LHeC.

Olaf Behnke
A brief review is presented of the precision QCD and electroweak physics potentials at a possible future Large Hadron electron Collider (LHeC). All presented results are taken from the recently released conceptional design report~\cite{cdr} (CDR), in which further references can be found.

Determination of the Integrated Luminosity at HERA using Elastic QED Compton Events.

Stefan Schmitt
A measurement of the integrated luminosity at the $ep$ collider HERA is presented, exploiting the elastic QED Compton process $ep\to e\gamma p$. The electron and the photon are detected in the backward calorimeter of the H1 experiment. The integrated luminosity of the data recorded in 2003 to 2007 is determined with a precision of \totalerr{}. The measurement is found to be compatible with the corresponding result obtained using the Bethe-Heitler process.

Searches for BSM Higgs at CMS.

J. Germander
These proceedings report the results on the Higgs Searches beyond the standard model at the CMS experiment with data collected during the 2011 LHC run at \unit{7}{\TeV}, corresponding to an integrated luminosity of about \unit{5}{\invfb}. Results for several models are shown from analyses performed by the CMS collaboration. No significant deviation from the standard model is found and limits on the Higgs mass are set for each physics scenario.

QCD NLO analysis of inclusive, charm and jet data (HERAPDF 1.7).

Krzysztof Nowak
A preliminary global NLO QCD analysis of the HERA data is presented. AThe following data sets are used in this analysis: the NC and CC inclusive DIS cross sections obtained from preliminary combination of the measurements from H1 and ZEUS based on HERA I and HERA II data at the nominal proton beam energy, the preliminary combined inclusive NC DIS cross sections at reduced proton beam energies, the inclusive jet cross sections from H1 and...

Precision Polarized SIDIS Experiments in Hall-A at 12 GeV JLab.

Kalyan Allada & Vincent Sulkosky
Single (SSA) and double spin asymmetries (DSA) in semi-inclusive DIS reactions using polarized nucleon targets provide a powerful method to probe transverse momentum dependent parton distribution functions (TMDs). The Jefferson Lab 12 GeV upgrade will provide a unique opportunity to perform precision measurements and to map out these multi-dimensional PDFs. Future plans for performing these measurements in Hall-A using the Solenoidal Large Intensity Device (SoLID) and polarized proton and $^3$He (neutron) targets are discussed. The...

$\alpha_{S}$ status.

Andre Hoang
A write-up was not submitted for this talk. Most of the material presented can be found in: S. Bethke, A. Hoang et al., Workshop on Precision Measurements of $\alpha_S$, arXiv:1110.0016.

Studies of vector boson+jet production with the ATLAS detector.

Camille Belanger-Champagne
The production of jets or b-jets in association with a W or Z boson in proton-proton collisions at 7~TeV at the LHC is an important test of quantum chromodynamics (QCD). Electron and muon decay channels of the Z and W bosons are studied. Cross sections have been measured up to high jet multiplicities with the ATLAS detector on data samples with integrated luminosities between 33~pb$^{-1}$ and 37~pb$^{-1}$. These measurements were compared to new higher-order QCD...

European XFEL Annual Report 2012

Massimo Altarelli

Electroweak Precision Measurements and Direct Higgs Searches at the Tevatron.

David Waters
The latest electroweak precision measurements and direct Higgs boson search results from the Tevatron are reviewed. Emphasis is placed on measurements for which the Tevatron is still competitive with the LHC. In the case of certain results, notably the precision measurements of the $W$ boson and top quark masses, the Tevatron results will remain world leading for a considerable period of time.

Linearly polarized Gluons and the Higgs Transverse Momentum Distribution.

Wilco J. Den Dunnen, Daniel Boer, Cristian Pisano, Marc Schlegel & Werner Vogelsang
We investigate the possible role of linearly polarized gluons in Higgs production from unpolarized $pp$ collisions. The transverse momentum distribution of the produced Higgs boson is found to exhibit a modulation with respect to the naive, unpolarized expectation, with the sign depending on the parity of the Higgs boson. The transverse momentum distribution of a scalar Higgs will, therefore, have a shape clearly different from a pseudo-scalar Higgs. We suggest that this effect can be...

Technical Design Report: Scientific Instrument Single Particles, Clusters, and Biomolecules (SPB)

Adrian Mancuso, Andrew Aquila, Gannon Borchers, Klaus Giewekemeyer & Nadja Reimers
This document builds on the preceding CDR and outlines technical specifications and designs for many of the components of the SPB instrument. More detailed design and modelling has been undertaken for certain long-lead time components, in particular the X-ray optics, as these require specification for procurement in the near future. For most other components, the level of detail described will not be as high, reflecting the timeline of the project with earliest beam expected to...

High Energy Exclusive Leptoproduction of the $\rho$-meson: Theory and Phenomenology.

I. V. Anikin, Adrien Besse, D. Yu. Ivanov, B. Pire, L. Szymanowski & S. Wallon
AWe describe the hard leptoproduction of transversally polarized rho-meson, up to twist~3 accuracy, including 2- and 3- particles Fock-states, in the HERA kinematics of high center-of-mass energy. We first build a model based on a simple approach to the unintegrated gluon density (the parton impact factor) that we compare with H1 and ZEUS data for the ratios of helicity amplitudes $T(\gamma^{*}_T \to \rho_T)/T(\gamma^{*}_L \to \rho_L)$ and $T(\gamma^{*}_T \to \rho_L)/T(\gamma^{*}_L \to \rho_L)$ and get a good...

Summary of the Heavy Flavour Working Group.

Jolanta Brodzicka, Massimo Corradi, Ingo Schienbein & Reinhard Schwienhorst
We review theoretical and phenomenological aspects of heavy flavour production as discussed in the heavy flavour working group of the DIS 2012. Recent theoretical progress includes approximate NNLO calculations for heavy quark structure functions in deep inelastic scattering, the extension of the ACOT heavy flavour scheme to jet production, and advances in top physics where the highlight is clearly the first complete NNLO QCD prediction for top pair production in the $q \bar{q}$ annihilation channel....

COMPASS results on transverse spin asymmetries in two-hadron production in SIDIS.

Christopher Braun
COMPASS is a fixed target experiment at CERN where nucleon spin structure and hadron spectroscopy are investigated. An important part of its physics program are the measurements of single spin asymmetries in semi-inclusive deep inelastic scattering on transversely polarized targets. Data on a deuteron target were taken in 2002-2004. After taking the first data on a transversely polarized proton target in 2007, a full year of data taking followed in 2010 to increase precision. In...

Heavy Flavour Production in ATLAS.

Adam Barton
ATLAS has studied heavy flavour production in a variety of decay channels and inclusive signatures including charmed mesons, jets originating from b-quarks and inclusive muons and electrons. Differential production cross sections for beauty and charm are extracted from these signatures and compared with a variety of theoretical predictions.

Elastic $Z^{0}$ production at HERA.

Takuya Nobe
Elastic $Z^{0}$ events $ep\rightarrow eZ^{0}p^{\left(*\right)}$ have been measured in $ep$ collisions at HERA using the ZEUS detector. The analysis is based on the data collected between 1996 and 2007, amounting to 496 pb$^{-1}$ of integrated luminosity. The $Z^{0}$ was measured in hadronic decay mode with elastic condition defined by $\eta_{max} < 3.0$, where $\eta_{max}$ is defined as the pseudorapidity of the energy deposit in the calorimeter closest to the proton beam direction. An excess of...

Registration Year

  • 2013

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