Experimental constraints from flavour changing processes and physics beyond the Standard Model

Flavour physics has a long tradition of paving the way for direct discoveries of new particles and interactions. Results over the last decade have placed stringent bounds on the parameter space of physics beyond the Standard Model. Early results from the LHC, and its dedicated flavour factory LHCb, have further tightened these constraints and reiterate the ongoing relevance of flavour studies. The experimental status of flavour observables in the charm and beauty sectors is reviewed in measurements of CP violation, neutral meson mixing, and measurements of rare decays.     

<Emphasis Type="Italic">B</Emphasis><Stack><Subscript>s</Subscript><Superscript>0</Superscript></Stack> physics at LHCb

The LHCb experiment is in preparation, to be ready for the start of the LHC. The physics which will be performed by LHCb is reviewed, focussing on what can be learnt fromB _s ⁰ mesons.     

Heavy flavour hadron spectroscopy: An overview

A comprehensive overview and some of the theoretical attempts towards understanding heavy flavour hadron spectroscopy are presented. Apart from the conventional quark structure (quark, antiquarks structure for the mesons and three-quarks structure of baryons) of hadrons, multiquark hadrons the hadron molecular states etc., also will be reviewed. Various issues and challenges in understanding the physics and dynamics of the quarks at the hadronic dimensions are highlighted. Looking into the present and future experimental prospects at different heavy flavour laboratories like BES-III, CLEO-c, BaBar, Belle, LHC etc., the scope for theoretical extensions of the present knowledge of heavy flavour physics would be very demanding. In this context, many relevant contributions from the forthcoming PANDA Facility are expected. Scopes and outlook of the hadron physics at the heavy flavour sector in view of the future experimental facilities are highlighted.     

Heavy flavour physics at the LHC

A summary of results in heavy flavour physics from Run 1 of the LHC is presented. Topics discussed include spectroscopy, mixing, CP violation and rare decays of charmed and beauty hadrons.     

Heavy ions at the LHC: Physics perspectives and experimental program

Ultrarelativisitc heavy ion physics is entering the new era of collider experiments with the start-up of RHIC at BNL and construction for detectors at LHC well under way. At this cross-roads, the article will give a summary of the experimental program and our current view of heavy ion physics at the LHC, concentrating in particular on physics topics that are different or unique compared to current facilities.     

Status of the LHCb experiment

The European Physical Journal C - LHCb is a dedicated experiment to study CP violation and other rare processes in the B meson system at LHC. It is designed to exploit the large sample of Bd and Bs...     

The LHCb L0 trigger and related detectors

The European Physical Journal C - The LHCb experiment will study CP violation and other rare phenomena using the b-hadrons produced at the LHC. A powerful trigger system is mandatory to select...     

Heavy ion collisions at CMS and quark-gluon plasma

One of the most actual goals in high energy physics is reaching the state of deconfinement of hadronic matter and studying the properties of resultant quark-gluon plasma (QGP). Jet production, as well as other hard processes, is considered to be an efficient probe for formation of QGP in future experiments on heavy ion collisions at LHC.The Compact Muon Solenoid (CMS) is the general purpose detector designed to run at the LHC and optimized mainly for the search of the Higgs boson in proton-proton collisions. However, a good muon system and electromagnetic and hadron calorimeters with fine granularity gives the possibility to cover several important aspects of the heavy ion physics. The production of heavy quarkonia Γ, Γ′, Γ″ through their muon decay channel and the energy loss of hard jets, are valuable processes for studying the phase transition from the hadronic matter to the plasma of deconfined quarks and gluons.     

Single top production in a non-minimal supersymmetric model

We study single top production at the LHC in a SUSY-QCD model with a heavy Dirac gluino. The presence of a heavy Dirac gluino allows for notable top-up flavour changing neutral currents. In this scenario, we find that the process ug→tg$ug\to tg$ gives the largest contribution to single top production via FCNCs at the LHC. The key features of this signal are that the top quark is produced very forward and that it is asymmetric to its anti-top counterpart, as the latter lacks a valence quark.     

Implications of LHC searches on SUSY particle spectra

We study the implications of LHC searches on SUSY particle spectra using flat scans of the 19-parameter pMSSM phase space. We apply constraints from flavour physics, g _μ −2, dark matter and earlier LEP and Tevatron searches. The sensitivity of the LHC SUSY searches with jets, leptons and missing energy is assessed by reproducing with fast simulation the recent CMS analyses after validation on benchmark points. We present results in terms of the fraction of pMSSM points compatible with all the constraints which are excluded by the LHC searches with 1 fb⁻¹ and 15 fb⁻¹ as a function of the mass of strongly and weakly interacting SUSY particles. We also discuss the suppression of Higgs production cross sections for the MSSM points not excluded and contrast the region of parameter space tested by the LHC data with the constraints from dark matter direct detection experiments.     

Large Hadron collider tests of the little Higgs model

The little Higgs model provides an alternative to traditional candidates for new physics at the TeV scale. The new heavy gauge bosons predicted by this model should be observable at the CERN Large Hadron Collider (LHC). We discuss how the LHC experiments could test the little Higgs model by studying the production and decay of these particles.     

Large hadron collider physics program: Compact muon solenoid experiment

The LHC physics program at CERN addresses some of the fundamental issues in particle physics and CMS experiment would concentrate on them. The CMS detector is designed for the search of Standard Model Higgs boson in the whole possible mass range. Also it will be sensitive to Higgs bosons in the minimal supersymmetric model and well adapted to searches for SUSY particles, new massive vector bosons, CP-violation in B-system, search for subtructure of quarks and leptons, etc. In the LHC heavy ion collisions the energy density would be well above the threshold for the possible formation of quark-gluon plasma.     

Heavy ions with the Large Hadron Collider and the ALICE detector

The Large Hadron Collider (LHC) under construction at CERN is also planned as a heavy ion collider with lead ions colliding at an energy of 2.7+2.7 ATeV. This corresponds to collisions of matter with cosmic rays of the utmost energies observed so far promising the study of new and exciting aspects of physics. Minor improvements of the newly commissioned lead ion source at the CERN SPS are necessary in order to provide a luminosity of L=2×10²⁷ cm^?2s^?1. The detector ALICE has been chosen as the third detector for the LHC and will be dedicated to the physics of these nuclear collisions and also to the large cross section physics in p+p collisions.     

Pair production of (<Emphasis Type="Italic">bc</Emphasis>) diquarks at the LHC

Production of a doubly heavy diquark pair (bc) + (\(\bar b\bar c\)) at the LHC is considered at the leading order of perturbative QCD. Several types of relativistic corrections are taken into account within the formalism of the relativistic quark model and the quasipotential approach. It is shown that contributions from subprocesses involving the color-sextet diquark production mechanism largely determine the cross section under the LHCb kinematical restrictions.     

Selected topics in Higgs physics at the LHC

In this talk I discuss a few selected topics in Higgs phenomenology at the LHC. After some brief remarks on the standard model Higgs I turn to more novel possibilities, discussing a heavy Higgs scenario, a light Higgs scenario and a no Higgs scenario. In the case of the light Higgs, I discuss briefly the physics opportunities afforded if it becomes possible to detect low angle scattered protons at the LHC.     

Probing new top physics at the LHCb experiment

We suggest that top quark physics can be studied at the LHCb experiment and that top quark production could be observed. Since LHCb covers a large pseudorapidity region in the forward direction, it has unique abilities to probe new physics in the top quark sector. Furthermore, we demonstrate that LHCb may be able to measure a t ?t production rate asymmetry and, thus, indirectly probe an anomalous forward-backward t ?t asymmetry in the forward region, a possibility suggested by the enhanced forward-backward asymmetry reported by the CDF experiment.     

Inclusive production at LHC energies

We consider the first LHC data for pp collisions in the framework of Regge theory. The integral cross sections and inclusive densities of secondaries are determined by the Pomeron exchange, and we present the corresponding predictions for them. The first measurements of inclusive densities in the midrapidity region are in agreement with these predictions. The contribution of the baryon-number transfer due to String Junction diffusion in the rapidity space is at the origin of the differences in the inclusive spectra of particle and antiparticle in the central region, and this effect could be significant at LHC energies. We discuss the first data of ALICE and LHCb collaborations on the baryon/antibaryon asymmetry at LHC.     

Signals of new physics in global event properties in pp collisions in the TeV energy domain: rapidity intervals

The study of possible new physics signals in global event properties in pp collisions in the TeV energy domain is extended from full phase-space to rapidity intervals experimentally accessible at LHC. The elbow structure in the total multiplicity distribution predicted in full phase-space is clearly present also in restricted rapidity intervals, leading to very strong charged particle correlations. It is also found that energy densities comparable to those reached in heavy ion collisions at RHIC could be attained in pp collisions at LHC.Received: 3 March 2004, Published online: 23 July 2004