abstract

We present an overview of the analyses performed by the two experiments at the Run II of the Tevatron searching for Higgs boson production. Especial effort has been done in the search for the Higgs boson predicted by the Standard Model. The good performance of the Tevatron would allow the experiments to be sensitive to the presence of the Higgs beyond the LEP limit by the end of Run II. In addition, analyses performed in the framework of models extending the Standard Model are already covering regions not excluded by previous experiments. Results from all these analyses and plans for the future will be discussed.

abstract

This contribution reviews the most recent theoretical developments concerning Higgs production at the Large Hadron Collider. Emphasis is put on the inclusive and exclusive cross sections for gluon fusion, both in the Standard Model and in the MSSM, as well as on the associated production with bottom quarks.

abstract

The final results of LEP on the searches for neutral Higgs bosons of the minimal supersymmetric extension of the Standard Model (MSSM) are reviewed. The highlight is put on the results derived in representative scenarios aimed at testing various challenges for the experimental detection, both at LEP and at hadron colliders (kinematics, vanishing branching fractions in key channels, CP violation in the Higgs sector).

abstract

This is a non exhaustive overview of Higgs physics at the LHC.

abstract

We present a strategy for a Higgs-boson search in its four-muon decay channel \({H}\to {ZZ^{(\ast )}}\to 4\mu \). Cuts used in this analysis are smooth functions of a 4-muon invariant mass and a priori optimized so as to maximize statistical chances of the Higgs boson observability independently of a mass at which it might appear. The Higgs boson then manifests itself as a \(4\mu \) resonance-like peak over the continuum \(M(4\mu )\) distribution and can be searched for using various statistical techniques. The most important theoretical and instrumental systematic errors as well as the fact that the search is conducted in a broad range of \(M(4\mu )\) invariant masses (115–600 GeV/\(c^2\)) are taken into account.

abstract

This article describes a study of a possible measurement at the CMS detector of the CP-parity of the Higgs boson \({\mit \Phi }\) using angular correlations in the \({\mit \Phi } \to ZZ \to e^+e^-\mu ^+\mu ^-\) process, which is a “golden plated channel” for Higgs boson searches at LHC. It will be shown that a measurement of the \(\xi \)-parameter describing a generalised \({\mit \Phi }{ZZ}\) coupling, which determines CP-parity of the Higgs boson, will be feasible at CMS. The precision of the measurement is sufficient for determination of CP-parity of the Higgs boson, in particular to distinguish between the scalar and pseudoscalar Higgs bosons.

abstract

The search of a Standard Model Higgs boson in the two photons channel with the ATLAS detector is reviewed with a particular emphasis on the expected detector performance. The results of the inclusive analysis on the most recent samples of full simulated events are reported. The overall discovery potential in this channel is finally updated including a discussion on NLO corrections.

abstract

A prospective analysis for the discovery of a light Standard Model Higgs boson in the CMS experiment at the Large Hadron Collider is presented. The analysis focuses on the inclusive single production \( p + p \rightarrow H + X\) and the Higgs boson decay channel \( H \rightarrow W W^{{(*)}} \rightarrow e^+ \nu e^- \bar {\nu }\), for a mass \(M_{ H}\) in the range \(120 \lt M_{ H} \lt 160\) GeV/\(c^{2}\). A full simulation of the CMS detector response is performed and emphasis is put on the use of detailed electron reconstruction, as well as on realistic treatment of background contamination and systematics. A Higgs boson of mass \(M_{H} \gtrsim 134\) GeV/\(c^2\) would be observed with a significance above 3 standard deviations in the \( e^+ \nu e^- \bar {\nu }\) channel alone for an integrated luminosity above 30 fb\(^{-1}\).

abstract

The calculation of the two-loop corrections to the partial width of an intermediate-mass Higgs boson decaying into a pair of photons is reviewed. The main focus lies on the electroweak (EW) contributions. The sum of the EW corrections ranges from \(-4\)% to 0% for a Higgs mass between 100 GeV and 150 GeV, while the complete correction at two-loop order amounts to less than \(\pm 1.5\)% in this regime.

abstract

We describe methods to identify \(\tau \) leptons produced in high energy \(p\bar {p}\) collisions (\(\sqrt {s} = 1.96 \) GeV) at the Tevatron, using the DØ detector. Different procedures used for discrimination against background particles misidentified as taus are also discussed. Finally, we present some physics results obtained using these methods to illustrate their performance.

abstract

The Standard Model Higgs discovery potential of CMS in the \(H \to WW \to \ell \nu \ell \nu \) channel is presented. The results are based on a full detector simulation and include the last theoretical developments for background and signal simulation. A first estimate of the expected systematics is also performed. If the Standard Model Higgs has a mass between 150 GeV and 180 GeV, it should be discovered with more than 5\(\sigma \) significance with a luminosity of 10 fb\(^{-1}\).

abstract

The standard model of particle physics does not predict sizable branching ratios of the Higgs boson to invisible final states. Nevertheless, a variety of models exist that predict branching ratios of up to 100% to invisible final states. Several experimental signatures can be used to search for an invisibly decayed Higgs boson. Searches carried out in the CMS and in the ATLAS collaboration will be reviewed.

abstract

NLO–QCD corrections to vector boson pair production via weak boson fusion have recently been calculated and implemented into flexible parton-level Monte Carlo programs. These allow for the computation of cross sections and kinematical distributions within realistic experimental cuts. We summarize the basic elements of the calculation and review phenomenological results for the LHC.

abstract

ATLAS is a general purpose experiment which will operate at the LHC. In the main focus of ATLAS is the investigation of the nature of the electroweak symmetry breaking, and therefore the search for the Higgs boson. Electrons, photons, muons, tau and \(b\)-jets are important components of the possible physics signatures expected. The expected quality of particle-ID impose strong requirements upon the performance of the detector, which has to be sensitive to the Higgs boson discovery over the full range of allowed masses. In this paper the detector performance in terms of particle identification is presented.

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Corrections of 10–30% for backgrounds to the \(H \to WW \to \ell ^+\ell ^-\not {\!p}_{\rm T}\) search in vector boson and gluon fusion at the LHC are reviewed to make the case for precise and accurate theoretical background predictions.

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A prospective analysis is presented for the discovery potential and properties measurement of the Standard Model Higgs boson with the CMS experiment at the LHC collider. The analysis focuses on the \(H \rightarrow Z Z^{{(*)}} \rightarrow \) \(4l + X\) channel for Higgs boson masses in the range \(120 \lesssim m_{ H} \lesssim 600\) GeV/\(c^2\). It relies on a full simulation of the detector response and usage of detailed lepton reconstruction tools. Emphasis is put on realistic strategies for the evaluation of experimental systematics and control of physics background processes.

abstract

A number of extremely high energy cosmic ray events have been observed by various collaborations. The existence of such events, above the Greisen-Zatsepin-Kuzmin (GZK) cut-off has to be explained by a top-down scenario involving exotic physics. Yet the results reported depend heavily on Monte Carlo procedures. The LHCf experiment will provide important data to calibrate the codes used in air shower simulations.

abstract

Results on QCD studies from the H1 and ZEUS Collaborations at the \(ep\) collider HERA are presented and their impact on LHC physics discussed.

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This report summarises some of the main results of the one year long workshop on the impact of HERA data on the physics program of the LHC.

abstract

The recent successes of the SM do not weaken the arguments in favor of New Physics residing at the TeV scale. Finding and identifying it represents the prime challenge for a generation of high energy physicists. To differentiate between different scenarios of New Physics we need to analyze their impact on flavor dynamics. A continuing comprehensive program of heavy flavor studies instrumentalizing the high sensitivity of CP analyses is intrinsically connected to LHC’s core mission. In \(B\) decays we can typically expect no more than moderate deviations from SM predictions. \(B_{\rm s}\) transitions provide an autonomous access to New Physics not prejudiced by \(\Delta M(B_{\rm s})|_{\rm exp}\simeq \Delta M(B_{\rm s})|_{\rm SM}\). Dedicated studies of charm and \(\tau \) decays offer unique opportunities to observe New Physics. One challenge is whether LHCb will be able to exploit LHC’s huge charm production rate to probe for CP asymmetries. Likewise, to which degree ATLAS/CMS can contribute to \(B\) physics and to searches for \(\tau \to 3l\). Yet to saturate the discovery potential for New Physics in beauty, charm and \(\tau \) decays we will need a comprehensive high quality data base that only a Super-Flavor Factory can provide.

abstract

The large datasets provided by the Tevatron \(p\bar {p}\) collider have offered CDF and DØ experiments unprecedented opportunities to measure \(B\) had- ron masses, lifetimes, and decay branching fractions with great precision, reconstruct and identify resonances that have never been observed before, and set stringent limits on many rare decays. In this paper, I summarize some of the recent heavy flavor results from the Tevatron.

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The Ring Imaging Cherenkov system of the LHCb experiment is presented, with particular emphasis on the status of the project.

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Rare loop-induced decays are sensitive to New Physics in many Standard Model extensions. In this paper we discuss the reconstruction of the radiative penguin decays \({B^0_{d}}\rightarrow {K^{*0}}\gamma \), \({B^0_{ s}}\rightarrow \phi \gamma \), \({B^0_{d}}\rightarrow \omega \gamma \), \({{\mit \Lambda }_b}\rightarrow {\mit \Lambda }\gamma \), the electroweak penguin decays \({B^0_{d}}\rightarrow K^{*0}\mu ^+\mu ^-\), \({B^+_{u}}\rightarrow {K^+}\mu ^+\mu ^-\), the gluonic penguin decays \({B^0_{d}} \rightarrow \phi {K^0_{\rm S}}\), \({B^0_{s}} \rightarrow \phi \phi \) and the decay \({B^0_{ s}} \rightarrow \mu ^+ \mu ^-\) at LHCb. The selection criteria, evaluated efficiencies, expected annual yields and \({B}\)/\({S}\) estimates are presented.

abstract

The potential of LHCb in the extraction of the angle \(\alpha \) from the analysis of the \(B\to (\rho \pi )^0\) and \(B\to (\rho \rho )^{\pm ,0}\) decays has been extensively studied. The expected performance are summarized in this document.

abstract

The preliminary results on the measurement of the \(D^+, D^0, J\)/\(\psi , b \bar b, {\mit \Upsilon }\) production cross sections performed by the HERA-B experiment in 920 GeV \(pA\) interactions are presented.

abstract

We present the sensitivity to the \(B_s\)–\(\overline {B}_s\) mixing phase \(\phi _s\) at LHCb, using decays proceeding through \(\overline {b} \to \overline {c}c\overline {s}\) quark-level transitions. The performance is assessed by means of toy Monte Carlo simulations, parameterized using the results of full Monte Carlo studies. Both the \(\overline {b} \to \overline {c}c\overline {s}\) decays to pure (\(B_s \to {\eta }_c \phi ,\,B_s \to D_s D_s,\,B_s\to J\)/\(\psi \eta \)) and to an admixture of CP eigenstates (\(B_s \to J\)/\(\psi \phi \)) are considered, and used to probe the \(B_s\)–\(\overline {B}_s\) mixing phase through a time-dependent mixing-induced CP measurement.

abstract

The LHCb experiment relies on an efficient trigger to select a rate up to 2 kHz of events useful for physics analysis from an initial rate of 10 MHz of visible collisions. In this contribution, we describe the different LHCb trigger algorithms and present their expected performance.

abstract

We discuss the latest studies on rare semileptonic decays of \(B\)-mesons and \({\mit \Lambda }_b\) at the ATLAS detector.

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The ability to perform precision measurements on the CKM angle \(\gamma \) in many different decay channels using \(B^0_s\), \(B^0_d\) and \(B^{\pm }\) decays is one of LHCb’s most exciting features, promising to thoroughly over-constrain the SM of CP violation and quark mixing. Here we will outline proposed methods and expected event yields and precisions on \(\gamma \) for several of these methods.

abstract

The study of heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) has revealed many, sometimes unexpected, properties of strongly interacting matter under extreme conditions. Systematic surveys of these collisions over a wide range of collision energy and system size have shown convincingly that at sufficiently high energies a dense, interacting medium is formed early on in the collision process. Many qualitative connections between experimental observations and fundamental concepts of the theory of strong interactions, QCD, have been established, including the formation of the initial collision state, the interaction of fast partons with the medium and the dynamics of the expansion of the medium. Still, many important question relating to the nature of the medium and the process of its formation remain to be answered. In this paper, I will discuss selected measurements from RHIC and point out opportunities for measurements in heavy ion collisions at the LHC.

abstract

Some of the new developments in the theory of heavy ion collisions are reviewed. Much of the last progress has been triggered by the high energies available at RHIC. In the near future, the LHC will extend the energy reach in heavy ions by a factor thirty and give access to new QCD regimes characterized by large densities and temperatures and corresponding modified evolution equations.

abstract

We have analyzed generic features of lepton pair production via multiphoton processes in peripheral heavy ion scattering. This process serves as an archetype reaction for perturbative QCD multigluon hard processes in collisions of ultrarelativistic nuclei. Explicit results for lepton pair production by annihilation of two photons from one nucleus and two photons from another one were obtained.

abstract

The study of heavy ion collisions at the Large Hadron Collider (LHC) represents an opportunity to study partonic matter at center-of-mass energies a factor of \(\sim 27\) times higher than currently possible. This dramatic increase in energy will allow the creation of strongly interacting matter at the highest energy density ever produced in the laboratory. The Compact Muon Solenoid (CMS) detector is ideally suited to study the rich physics of Quantum Chromodynamics and the strong interaction in this new energy region. A brief overview of the heavy ion physics capabilities of the CMS detector is presented.

abstract

This paper discusses some aspects of the initial proton–proton physics program with the ALICE experiment at LHC. For initial low luminosity runs ALICE has possibilities comparable to the two dedicated \(p+p\) experiments at LHC plus the advantage of a low \(p_{\rm T}\) acceptance in the central barrel. It will therefore play an important role in the understanding of the minimum bias proton–proton collisions in the LHC energy regime. The experiment is briefly described and aspects of the initial proton–proton program are discussed in terms of physics, statistics, detector performance and analysis.

abstract

The forthcoming ALICE experiment at LHC will have the unique capability of identifying particles with a high separation power and it is expected to give new insights into dynamics of relativistic heavy ion collisions, e.g. the interplay between soft and hard processes in the hadron production as discussed here. The results obtained from the heavy ion experiments at the Relativistic Heavy Ion Collider (RHIC) and the expectations at the unprecedented LHC energies will be also shown. Particle ratios from equilibrium and non equilibrium scenarios are presented. Furthermore, hadron momentum spectra and the production of some resonances as will be measured by ALICE are discussed.

abstract

Measurements of heavy quarkonia states, such as \(J\)/\({\mit \Psi }\), \({\mit \Psi }\,'\), \({\mit \Upsilon }\), \({\mit \Upsilon }\,'\), and high \(p_{\rm T}\) charged particles carry important information to characterize the quark gluon plasma produced in high energy heavy ion collisions at LHC. The ALICE Transition Radiation Detector (TRD) provides clear separation of electrons from the large background of pions and improves the tracking performance of ALICE central barrel detectors. The TRD also provides a fast trigger signal on high transverse momentum charged particles. In this paper we present the capabilities of heavy quarkonia reconstruction and jet trigger of TRD.

abstract

The ability of the ALICE detector to reconstruct the \(K^*(892)^0\) and \({\mit \Lambda }(1520)\) resonances in \(p\)–\(p\) and Pb–Pb collisions at LHC energies has been investigated. PYTHIA events for \(p\)–\(p\) collisions and HIJING events for Pb–Pb collisions have been generated and fully reconstructed. The \(K^*(892)^0\) and \({\mit \Lambda }(1520)\) were identified by their hadronic decay into \(\pi K\) and \(pK\), respectively, through an invariant mass analysis. The combinatorial background has been evaluated by the event-mixing technique for \(p\)–\(p\) events and by the like-sign technique for the Pb–Pb events.

abstract

Limiting fragmentation in hadronic collisions is analyzed in the framework of the \(k_\perp \) factorization and the nonlinear Balitsky–Kovchegov equation. Reasonable agreement with the experimental data is obtained. It is concluded that in order to obtain the limiting fragmentation, the factorization in the parton distributions in the target and the projectile is necessary as well as the independence of the parton distributions in the target of the scales in the process.

abstract

In the present talk we report results from a study of the performance for the detection in ALICE of (a) \(B \to e + X\) decays with the central barrel and (b) \(B \to \mu + X\) decays with the muon spectrometer. We include an evaluation of the expected statistical and systematic uncertainties on the measurement of the cross section of beauty hadrons. We also discuss the possibility of detecting the modifications of beauty hadrons’ transverse momentum (\(p_{\rm t}\)) distribution induced by in-medium gluon radiation calculated by a phenomenological model.

abstract

The Large Hadron Collider will provide an opportunity to study Pb–Pb collisions at \(\sqrt {s_{NN}} = 5.5\) TeV as well as other nucleus–nucleus collision systems including proton–nucleus collisions. The ATLAS apparatus with its hermetic calorimetry, a precise silicon inner detector and a background-free standalone muon spectrometer is well suited to study a wide range of phenomena in nucleus–nucleus collisions at LHC. This talk reports on the studies of the ATLAS experiment capabilities for heavy ion physics at LHC. These studies show a very good potential of the ATLAS detector for measuring global properties of nucleus–nucleus collisions such as charged particle multiplicities and azimuthal anisotropies as well as heavy quark and quarkonia production and jet quenching. The results from the first round of studies based on the full simulations of the detector response are presented. Ongoing activities are also briefly summarized.

abstract

I discuss here some of the deeper connections between the physics studied at the LHC (electroweak phase transition, physics beyond the Standard Model, extra dimensions) and some of the most important issues in the field of particle astrophysics and cosmology (dark matter, primordial gravitational waves, black holes, \(\ldots \)).

abstract

The prospects for physics at the LHC are discussed, starting with the foretaste, preparation (and perhaps scoop) provided by the Tevatron, in particular, and then continuing through the successive phases of LHC operation. These include the start-up phase, the early physics runs, the possible search for new physics in double diffraction, the continuation to nominal LHC running, and the possible upgrade of the LHC luminosity. Emphasis is placed on the prospects for Higgs physics and the search for supersymmetry. The progress and discoveries of the LHC will set the time-scale and agenda for the major future accelerator projects that will follow it.