244 Works

Subleading-$N_c$ improved parton showers.

Simon Plaetzer & Malin Sjoedahl
We present an algorithm for improving subsequent parton shower emissions by full SU(3) colour correlations in the framework of a dipole-type shower. As a proof of concept, we present results from the first implementation of such an algorithm for a final state shower.

Searches for Fourth Generation Heavy Quarks with the ATLAS Detector.

Jiahang Zhong
The addition of one or more generations of heavy fermions is a natural extension to the Standard Model. Fourth generation heavy quarks can be produced at the LHC at rates that can be observed in the 2011 data samples, depending on the quark mass. The talk presents results from searches performed by the ATLAS collaboration for fourth generation quarks decaying via several potential decay channels.

Searches at ZEUS.

Stefano Antonelli
The results of recent searches for scalar and vector leptoquarks and anomalous single top production in $e^{\pm}$ collisions at HERA are presented. The searches make use of the full ZEUS data set corresponding to $0.5 \thickspace\invfemtobarn$. No evidence for leptoquarks signals is found and limits are set on the Yukawa coupling, $\lambda$, as a function of the leptoquark mass for different leptoquark types within the Buchm\"{u}ller-R\"{u}ckl-Wyler model. No evidence for top production is found and...

Search for the rare decays $B \rightarrow \mu^+\mu^-$ with the CMS detector.

Franco Simonetto
I summarize here the results of a search for the rare decays $B^0 \rightarrow \mu^+\mu^-$ and $B^0_s\rightarrow \mu^+\mu^-$, based on a sample of data collected by the CMS detector from $pp$ collisions at $\sqrt{s} =7$ \TeV, corresponding to an integrated luminosity of 4.9 \invfb . No excess of events over the expected background is observed. The resulting upper limits on the branching fractions are \mbox{${\cal B}(B_s^0 \rightarrow \mu^+ \mu^- ) < 7.7 \times 10^{-9}$} and...

Precision Measurements of the Proton Structure.

Iris Abt
The ``proton structure'' is a wide field. Discussed are predominantly the precision measurements of the proton structure functions at HERA and some of their implications for the LHC measurements. In addition, a discussion of what a proton structure function represents is provided. Finally, a connection to nuclear physics is attempted.

Using the BFKL Resummation to Fit DIS Data: Collinear and Running Coupling Effects

M. Hentschinski, A. Sabio Vera & C. Salas
20th International Workshop on Deep-Inelastic Scattering and Related Subjects, DIS 2012, Bonn, Germany, 26 Mar 2012 - 30 Mar 2012; Hamburg : Deutsches Elektronen-Synchrotron, DESY 429-432 (2012). doi:10.3204/DESY-PROC-2012-02/97

Searches for the standard model scalar boson in CMS and for new physics in ATLAS and CMS.

Barbara Clerbaux
Latest LHC results are reported focussing on the search for the standard model scalar boson, as well as a selection of searches for new physics beyond the standard model.

The ATLAS Upgrade programme.

Claudia Gemme
After the first successful years of LHC running, plans are actively advancing for a series of upgrades leading eventually to about five times the design-luminosity some 10-years from now. uCoping with the high instantaneous and integrated luminosity will be a great challenge for the ATLAS detector and will require changes in most of the subsystems, specially those at low radii and large pseudorapidity, as well as in its trigger architecture. Plans to consolidate and improve...

Top Quark Pair Production beyond the Next-to-Leading Order.

Valentin Ahrens, Andrea Ferroglia, Matthias Neubert, Ben D. Pecjak & Li Lin Yang
We report on recent calculations of the total cross section and differential distributions of top quark pair production at hardon colliders, including the invariant mass distribution, the transverse momentum and rapidity distributions, as well as the forward-backward asymmetry. The calculations are based on soft gluon resummation at the next-to-next-to-leading logarithmic accuracy.

Search for Heavy Stable Charged Particles with the CMS detector at the LHC.

Loic Quertenmont
Heavy Stable (or quasi-stable) Charged Particles (HSCP) are predicted by various extensions to the Standard Model of the fundamental interactions among elementary particles. If this prediction reveals to be true, such particles should be produced at the Large Hadron Collider (LHC) and observable with the Compact Muon Solenoid (CMS) detector. Results of the search for slowly moving (or stopped) HSCP with an integrated luminosity of 4.7~fb$^{-1}$ (0.9~fb$^{-1}$) is described.

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...

Overview of Deeply Virtual Compton Scattering at HERMES.

Morgan Murray
Deeply Virtual Compton Scattering represents the best experimental channel through which to understand Generalised Parton Distributions. The HERMES experiment measured the most diverse set of DVCS results of any experiment; this talk discusses the most recent sets of DVCS results released by HERMES and the unique experimental conditions found at HERMES that facilitated the measurements. We also examine the various ways in which the HERMES experimental measurements are being used to constrain GPDs and how...

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...

XFEL: The European X-Ray Free-Electron Laser - Technical Design Report

R. Abela, A. Aghababyan, M. Altarelli, C. Altucci, G. Amatuni, P. Anfinrud, P. Audebert, V. Ayvazyan, N. Baboi, J. Baehr, V. Balandin, R. Bandelmann, J. Becker, B. Beutner, C. Blome, I. Bohnet, A. Bolzmann, C. Bostedt, Y. Bozhko, A. Brandt, S. Bratos, C. Bressler, R. Brinkmann, O. Brovko, H. Brück … & A. Zolotov

Jets, W/Z and Top Quark Production at the LHC and Status of the Higgs Boson Searches at ATLAS.

Oliver Kortner
Until the end of 2011 the ATLAS and CMS experiments have each analysed up to 5~fb$^{-1}$ of $pp$ collision data at $\sqrt{s}=7$~TeV. Their studies show excellent agreement between Standard Model predictions and experimental measurements for the production of jets, $W/Z$ bosons, and top quarks. The ATLAS experiment has been able to exclude a Standard Model Higgs boson at 95\% confidence level in the mass intervals $\unit{110}{\GeV} < m_H < \unit{117.5}{\GeV}$, $\unit{118.5}{\GeV} < m_H < \unit{122.5}{\GeV}$,...

Differential and total cross sections for top pair and single top production.

Nikolaos Kidonakis
I present theoretical results at approximate NNLO from NNLL resummation for top quark production at the LHC and the Tevatron, including new results at 8 TeV LHC energy. Total cross sections are shown for $t{\bar t}$ production, for single top production in the $t$ and $s$ channels and via associated $tW$ production, and for associated $tH^-$ production. Top quark transverse momentum and rapidity distributions in $t{\bar t}$ production are also presented, as well as new...

Physics with Electron-Ion Collisions at EIC.

J. H. Lee
Nuclei and nucleons probed in DIS and diffractive processes in the high-energy (small-x) regime open a new precision window into fundamental questions in QCD. The proposed Electron-Ion Collider (EIC) is a new high-energy and high-luminosity polarized electron-ion/polarized proton machine. The design offers an unprecedented access to explore the nature of QCD matter and strong color fields. In particular, the new collider will allow us to reach and explore the regime where the gluon density saturates,...

Prompt photon measurements with the ATLAS detector.

Leonardo Carminati
An overview of the main prompt photon measurements with the ATLAS detector is presented. The production cross sections for inclusive photons, photon plus jets and diphotons have been measured with 37 pb$^{-1}$ of $pp$ collisions at $\sqrt{s}$=7 TeV collected at the LHC in 2010. Data have been found to be in fair agreement with next-to-leading order perturbative QCD calculations. The overall picture confirms that QCD photons are well understood in ATLAS laying solid foundations for...

Neutrino Deep Inelastic Scattering with the Minerva Experiment.

Joel Mousseau
The \Minerva\space experiment, located in the NuMI beam at Fermilab, is in a position to significantly add to the world knowledge of DIS. Current neutrino DIS data contains poorly understood nuclear effects. In order to investigate these nuclear effects, \Minerva\space has installed nuclear targets of C, Fe and Pb in the same beam to measure the Fe/C and Pb/C ratios of DIS cross sections. While many uncertainties due to neutrino flux will cancel out in...

One-Hadron transverse target spin asymmetries at COMPASS.

Christoph Adolph
The measurements of single spin asymmetries in semi-inclusive deep inelastic scattering on a transversely polarized target are an important part of the COMPASS physics program. By measuring the spin dependent azimuthal asymmetries in hadron production one can access both transversity - using the Collins fragmentation function - and the Sivers distribution function. The COMPASS collaboration has measured these asymmetries in the scattering of a $160\,\mbox{GeV}/c$ polarized $\mu^+$ beam off a transversely polarized $^6$LiD (deuteron) target...

Searches for Large Extra Dimensions, Leptoquarks and Heavy Quarks at CMS.

Sushil Singh Chauhan
We present results from several searches for physics beyond the standard model involving large extra dimensions, leptoquarks, and heavy quarks at $\sqrt s =$ 7 TeV with the CMS experiment. Many different final states are analyzed using the data collected in 2010 and 2011 corresponding to an integrated luminosity up to $5.0fb^{-1}$. The results are used to set new limits on the scale of large extra dimensions and on the masses of leptoquarks and heavy...

The MSSM After Two Years of LHC Running.

Felix Bruemmer
The Minimal Supersymmetric Standard Model is increasingly getting constrained by the null results from squark and gluino searches at the LHC, and by the indications for a Higgs around 125 GeV. This talk presents a theorist's (biased) view of the impact of these constraints, with a focus on recent work.

Some Z' and W' Models facing current LHC Searches.

Ennio Salvioni
We present the implications of data collected by ATLAS and CMS in 2011 on some classes of $Z'$ and $W'$ models. We remark how the strongest bounds, coming for example from searches in final states containing leptons, do not apply to some theoretically well-motivated resonances, and discuss where signals from such states would appear.

The NLO jet vertex for Mueller-Navelet and forward jets in the small-cone approximation.

Dmitry Yu. Ivanov & Alessandro Papa
We calculate in the next-to-leading order the impact factor (vertex) for the production of a forward high-$p_T$ jet, in the approximation of small aperture of the jet cone in the pseudorapidity-azimuthal angle plane. The final expression for the vertex turns out to be simple and easy to implement in numerical calculations.

Conceptual Design Report: Scientific Instrument High Energy Density Physics (HED)

Motoaki Nakatsutsumi & Thomas Tschentscher
High energy density (HED) matter is defined as having an energy density above $10^{11}$ $J•m^{-3}$, which is equivalent to 100 GPa (1 Mbar) pressure and 500 T magnetic pressure. The scientific objectives of the High Energy Density Physics instrument (HED instrument) at the European XFEL are to create and explore HED states using the particular features of X-ray free-electron laser (FEL) radiation. Strongly excited solid but below-HED states are also considered to be a key...

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