abstract

This write-up represents a very compact version of a status report of the LHC project, a little more than a year before first beams will be injected. This status report is based on very recent extensive presentations to CERN Council and its Committees, by the LHC Project Leader (L. Evans) and the present author. Additional input was provided on behalf of ATLAS (P. Jenni), CMS (T.S. Virdee), LHCb (T. Nakada), ALICE (J. Schukraft), TOTEM (E. Radermacher) and LCG (L. Robertson).

abstract

The status of the construction and installation of CMS detector is reviewed. The 4T magnet is cold since end of February 2006. Its commissioning up to the nominal field started in July 2006 allowing a Cosmic Challenge in which elements of the final detector are involved. All big mechanical pieces equipped with muons chambers have been assembled in the surface hall SX5. Since mid July the detector is closed with commissioned HCAL, two ECAL supermodules and representative elements of the silicon tracker. The trigger system as well as the DAQ are tested. After the achievement of the physics TDR, CMS is now ready for the promising signal hunting.

abstract

The present status of the ATLAS project is briefly described.

abstract

LHCb is designed to search for physics beyond the Standard Model by studying CP violation and other rare processes in the \(B\) meson system with high precision at LHC. It has a flexible trigger system efficient for both leptonic and hadronic final states, particle identification capability over large momentum range and excellent decay time resolution. Construction and installation of various detector components are advancing well and the experiment is expected to be ready for the start-up of the LHC operation.

abstract

The ALICE experiment, under construction at the Large Hadron Collider, has been designed to study the behavior of nuclear matter under extreme conditions of energy density and temperature, via a simultaneous measurement of many observables. The ALICE setup comprises a multipurpose complex of tracking and particle-identification devices installed in a large solenoid magnet and a muon detection arm in the forward rapidity region. Characteristics and construction status of the main ALICE sub-detectors will be discussed.

abstract

A brief unconventional review of Standard Model physics, containing no plots.

abstract

With our current knowledge limited by the absence of physics data, I review our expectations from standard processes measurements at the LHC. Focusing on charged and neutral current processes, I illustrate how their measurement will constrain our uncertainties on discovery physics, and give some arguments about our precision goal for the \(W\) mass measurement. Detailed analysis reveals that there is no reason to believe we can not measure this fundamental parameter to about 5 MeV. This sets a natural goal of about 500 MeV for the top mass; to decide whether this is realistic requires further investigation.

abstract

This conference report presents a compilation of some of the latest results on prospects for Extra Dimensions and Extra Gauge Bosons Models with two general purpose detectors of the Large Hadron Collider (LHC) at the European Laboratory for Particle Physics (CERN): A Toroidal LHC ApparatuS (ATLAS) and the Compact Muon Solenoid (CMS). The results presented here correspond, in most of the cases, to full simulation and full reconstruction of the hadron interactions at 14 TeV center of mass energy at low and(or) high luminosity. In general, theoretical and systematic uncertainties are considered in the final results.

abstract

Recent results on searches for physics beyond the Standard Model from the CDF and DØ Collaborations at the \(p\bar {p}\) collider Tevatron are presented and their impact on LHC physics discussed.

abstract

Selected recent QCD and top-quark results from the Tevatron are reviewed, aiming to illustrate progression from basic studies of QCD processes to verification of perturbative calculations and Monte Carlo simulation tools, and to their applications in more novel and complex cases, like top-quark studies and searches for new physics.

abstract

I present recent Tevatron Run II results from CDF and DØ on the production and decay properties of the \(W\) boson.

abstract

We investigate the CMS potential for the observation and study of the \({p}{p}\to {Z^0}{Z^0}\to {e^+e^-}{e^+e^-}\) and \({p}{p}\to W{Z^0}\to 3\ell \ (\ell =e,\mu )\) reactions, using fully simulated signal and background samples. It is shown that these processes are potentially accessible with early CMS data, thanks to relatively high production cross sections at LHC energies, together with clear signatures of the multi-lepton final states. The main systematic effects relevant for cross section measurements with 1 and 10 fb\(^{-1}\) of data are addressed. We demonstrate that multiple gauge-boson production in \({p}{p}\) collisions at LHC energies can be observed in the early phase of the experiment, with an integrated luminosity of 1 fb\(^{-1}\) or less.

abstract

Recent QCD studies performed within ATLAS will be shown. QCD generators have been tuned in order to have a good description of the available minimum bias and underlying event data. Their predictions at the LHC energy and the reconstruction of events in ATLAS have also been studied. Jet physics analysis has been performed as well: to study how a measurement of the inclusive jet cross section could help on constraining parton density functions, how well dijet azimuthal decorrelations can be measured and how to use multi-jet events to calibrate the detector.

abstract

Given the big cross section for \(t\bar {t}\) production in proton-proton collisions at 14 TeV, the LHC with its high luminosity will be, among others, a top factory, allowing a precision measurement of the top quark mass. Based on a detailed simulation of the CMS detector, the following top mass reconstruction accuracies are possible in the respective final states with the present knowledge of experimental and theoretical uncertainties. \[ \begin {array}{lcl} \Delta m_t(\text {dileptonic}, 1~{\rm fb}^{-1}) &=& \pm 1.5\ {\rm stat.}\ \pm 2.9\ {\rm syst.}\ {\rm GeV}\,/\,c^2\\ \Delta m_t(\text {semileptonic}, 1~{\rm fb}^{-1}) &=& \pm 0.7\ {\rm stat.}\ \pm 1.9\ {\rm syst.}\ {\rm GeV}\,/\,c^2\\ \Delta m_t(\text {fully hadronic}, 1~{\rm fb}^{-1}) &=& \pm 0.6\ {\rm stat.}\ \pm 4.2\ {\rm syst.}\ {\rm GeV}\,/\,c^2\\ \Delta m_t(\text {dileptonic}, 10~{\rm fb}^{-1}) &=& \pm 0.5\ {\rm stat.}\ \pm 1.1\ {\rm syst.}\ {\rm GeV}\,/\,c^2\\ \Delta m_t(\text {semileptonic}, 10~{\rm fb}^{-1}) &=& \pm 0.2\ {\rm stat.}\ \pm 1.1\ {\rm syst.}\ {\rm GeV}\,/\,c^2\\ \Delta m_t(J\,/\,{\mit \Psi }, 20~{\rm fb}^{-1}) &=& \pm 1.2\ {\rm stat.}\ \pm 1.5\ {\rm syst.}\ {\rm GeV}\,/\,c^2\\ \end {array} \] A combined top mass accuracy of \(\mathcal {O}(1\) GeV/\(c^2\)) for 10–20 fb\(^{-1}\) of well-understood CMS data will be feasible.

abstract

We discuss a mechanism of double protection of the Higgs potential by supersymmetry and by a global symmetry. This occurs in supersymmetric models in which the Higgs boson is a Goldstone boson of a spontaneously broken approximate global symmetry, as in little Higgs. In such models the parameters of the electroweak sector require no fine-tuning at all.

abstract

The underlying event (UE), the softer component of the collision accompanying the hard scattering, accounts for a large fraction of the activity in terms of multiplicity and momentum of the observed particles. A brief review of the current status of the phenomenological studies, theoretical models and feasibility study for nominal CMS conditions at low luminosity is given.

abstract

A first feasibility study of the search for a new heavy charged gauge boson with the CMS detector at the Large Hadron Collider LHC is presented. The used model assumes the existence of a heavy carbon copy of the Standard Model \(W\) (Reference Model by Altarelli), generically denoted as \(W\,'\). Such a boson has been investigated in the decay channel \(W\,' \rightarrow \mu \nu \) using the full detector simulation including minimum bias events (pile-up) according to the luminosity expected in the first years. All relevant Standard Model backgrounds have been considered. Such a new boson is expected to be discovered, if existing, with a mass up to 4.6 TeV for an integrated luminosity of \(10\,{\rm fb}^{-1}\). The range can be expanded to 6.1 TeV with an integrated luminosity of \(300\,{\rm fb}^{-1}\). If no signs for a \(W\,'\) boson appear 95% CL exclusion limits of 4.7 TeV and 6.2 TeV can be set, respectively.

abstract

The search for Universal Extra Dimensions for four values of the compactification radius in the \(4e, 4\mu \) and \(2e\,2\mu \) channels is presented. It is shown that the CMS detector is sensitive up to \(R^{-1}= 900\) GeV/\(c^2\) for an integrated luminosity of 30 fb\(^{-1}\).

abstract

The expected signal sensitivity of the \({\rho _{\rm TC} \to W + Z \to 3\ell + \nu }\) decay channel is studied for the CMS detector, under the Technicolour “Straw Man” model. It shows a signal discovery potential at integrated luminosities starting from \(\int Ldt \simeq 4\) fb\(^{-1}\). Secondly, the CMS discovery potential of the heavy Majorana neutrino \(N_e\) and the right-handed gauge boson \(W_{\rm R}\) is demonstrated, under the minimal LR symmetric model, at an early stage of the low luminosity running.

abstract

At the Large Hadron Collider dileptonic \(t\bar t({\rm +jets})\) events can be selected with a relatively high signal-to-noise ratio and efficiency, with background events produced via Standard Model diagrams. Within the clean sample of these events, both isolated leptons have an opposite electric charge. In several models beyond the Standard Model \(tt\) / \(\bar t \bar t(+{\rm jets})\) topologies are predicted, kinematically similar to the Standard Model \(t\bar t({\rm +jets})\) signature, where both leptons have an equal electric charge. Such a signal of new physics can be diluted by the mis-identification of the leptons or their electric charge in Standard Model \(t\bar t({\rm +jets})\) events. The observability of an excess of same-charge dilepton signals above the mis-reconstruction of the Standard Model background is presented, assuming the same topology. With an integrated luminosity of \(30 \, \mathrm {fb^{-1}}\), a same-charge dilepton signature of \(pp \to tt\) / \(\bar t \bar t\) events with a cross section larger than \(1.2 \, \mathrm {pb}\) is visible in the measurement of the ratio between same-charge and opposite-charge lepton pair events [J. D’Hondt, S. Lowette, G. Hammad, J. Heyninck, P. Van Mulders, “Observability of same-charge lepton topology in dileptonic events \(t \bar t\)”, CERN-CMS-NOTE-2006-065.]

abstract

GASTOF (Gas Time-of-Flight) detector is a Cherenkov detector proposed for very precise (\(\delta t\sim 10\)–20 ps) arrival time measurements of forward protons at some 420 m from the central detectors of CMS and ATLAS. Such an excellent time resolution will allow by \(z\)-by-timing technique for precise measurement of the \(z\)-coordinate of the event vertex in exclusive production at the LHC, when two colliding protons are scattered at very small angles. In the paper we present first GASTOF prototype, simulations of its performance as well as first tests using a cosmic muon telescope.

abstract

The study of the \(Z\) boson at the ATLAS experiment provides several interesting aspects. The measurements of cross-section and transverse momentum spectrum (\(p_{\rm t}\)) of the \(Z\) boson at ATLAS provide additional tests of the standard model and may be sensitive to exotic physics processes. \(Z\) boson production is also a common background process for many other physics analysis and must be understood very well. The achievable precision of the cross-section \(\sigma (pp \rightarrow Z\) / \(\gamma \rightarrow \mu ^+ \mu ^ -)\) with first data of LHC at the ATLAS detector are discussed.

abstract

We present our recent study of \(I=1\) / 2 scalar (\(\kappa \)) and axial vector mesons (\(K_1\)) in the quenched approximation. Our results show that \(\kappa \) meson does not agree with recent experimental values.

abstract

A study is presented of the \(WW\) scattering in the absence of a light Higgs Boson. The work is done within the Electroweak Chiral Lagrangian (EWChL) framework, which is extended to high energies using the Padé unitarisation protocol, resulting in potentially new resonances. The generated signal and background processes are simulated using the ATLAS fast simulation package and the discovery potential for multiple scenarios is demonstrated.

abstract

This paper presents results from studies on observability of \(Z'\) particles and Randall–Sundrum gravitons in the dimuon channel in the CMS detector. Full detector simulation and reconstruction were carried out to derive both the discovery potential and results for model discrimination. Effects of systematic uncertainties on the expected reach of the CMS experiment are also presented.

abstract

At the LHC, millions of top quark pairs will be produced each year and already during the first LHC runs, a large and clean sample of them can be selected. The properties of the top quark can be extracted with great precision and with one of the most complex event topologies predicted by the SM, it will play an essential role during the detector commissioning phase. Understanding the detector response in such events in this new energy regime early during LHC operation is essential when searching for predicted signals from new physics models.

abstract

We present a strategy for the direct measurement of the \(WW\) production rate at the LHC with ATLAS. Sensitivity limits on anomalous \(WWZ\) and \(WW\gamma \) couplings are assessed with account of the effects of higher order QCD corrections and contributions from other theoretical and detector related systematics.

abstract

A brief review of SUSY physics in the advent of the LHC is presented.

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Recent results on searches for SUSY particles at the Tevatron are presented.

abstract

A full simulation study with the detector CMS is presented. The Leptons + Jets + Missing Energy (\(l = e,\mu \)) final state for SUSY events is investigated at mSUGRA benchmark point LM1. The end point in the dilepton pair invariant mass distribution is reconstructed and a scan of the \(\left (m_{0},\, m_{1/2}\right )\) plane is performed in order to determine the observability reach.

abstract

After revisiting the hierarchy problem of the Standard Model and its implications for the scale of New Physics, I consider the fine tuning problem of electroweak symmetry breaking in two main scenarios beyond the Standard Model: SUSY and Little Higgs models. The main conclusions are that New Physics should appear on the reach of the LHC; that some SUSY models can solve the hierarchy problem with acceptable residual fine tuning and, finally, that Little Higgs models generically suffer from large tunings, many times hidden.

abstract

We search for the Technicolor process \(\rho _{\rm T}/\omega \rightarrow \pi _{\rm T} W \) using events with one electron and two jets in 388 pb\(^{-1}\) of integrated luminosity recorded by the DØ experiment at Fermilab. As predicted by the Technicolor Straw Man Model (TCSM2) [K. Lane, S. Mrenna, Phys. Rev. D67, 115011 (2003)], \(\pi _{\rm T}\)’s decay dominantly into \(b\overline {b}\), \(b\overline {c}\), or \(\overline {b}c\), depending on their charge. We select events containing \(b\) and \(c\)-quarks by identifying their secondary decay vertices within jets. We present two analysis methods based on topological variables, one is cut-based and the other using neural networks for separation of signal and backgrounds. In the absence of an observed excess above the standard model prediction for expected backgrounds we define an excluded region, as a function of \(\rho _{\rm T}\) and \(\pi _{\rm T}\) masses and a given set of model parameters.

abstract

With the imminent start of the ATLAS data taking in 2007, the well considered strategy is necessary for the good understanding of the detector performance from in situ calibration and the realistic estimation of the Standard Model background. These are urgent issues for the new physics discovery channels especially for the SUSY searches in the early data taking of LHC run. The talk starts with the brief overview of the ATLAS detector and the calibration commissioning, then the realistic background estimation using real data and the matrix element calculation continues. Finally the newly obtained SUSY discovery potential with newly estimated backgrounds is presented.

abstract

\(R\)-hadrons are massive, meta-stable particles predicted in several Supersymmetry scenarios. Studies exploring the discovery potential of \(R\)-hadrons at the ATLAS detector have mainly focused on gluino \(R\)-hadrons. These studies have shown that gluino \(R\)-hadrons should be discovered in early running of the LHC, that they are easily isolated by simple cuts and that their mass can be measured to an accuracy of a few percent.

abstract

The search for the heavy, neutral MSSM Higgs bosons decaying into two \(\tau \) leptons is presented. The event selections and final discovery reach, with 30 fb\(^{-1}\), for the CMS experiment are shown.

abstract

In this talk we analyse the claim that supersymmetry (SUSY) naturally accounts for the observed dark matter density. In many cases, it is necessary to tune the parameters of a SUSY model to fit the WMAP data. We provide a quantitative analysis of the degree of tuning required for different annihilation channels. Some regions are natural, requiring no tuning at all, whereas others require tuning at the \(0.1\%\) level.

abstract

Methods to measure the sparticle masses with the ATLAS detector at the LHC are reported. The supersymmetric phenomenology is first briefly discussed in the context of the mSUGRA constrained model. Many examples of recent studies aiming at measuring the sparticle masses are then described. Most of these examples are based on recent full simulation of the ATLAS detector.

abstract

SU4 low mass SUSY model was analysed at ATLAS with full Geant4 simulation. With a production cross section of 270 pb and masses in the range 60–450 GeV, SU4 seems to be a promising target for SUSY searches with early ATLAS data. By establishing proper event selection criteria Standard Model backgrounds can be suppressed to the S/B level of about 3 in the inclusive searches, higher than 4 in the light stop search from the decay \(\tilde {g}\rightarrow \tilde {t}_1 t\) and above 1 in the right squark search from \(\tilde {q}_{\rm R} \tilde {q}_{\rm R}\) events.

abstract

We present the program package SUSY-HIT SUspect-SdecaY-Hdecay-InTerface for the computation of supersymmetric particle decays within the framework of the Minimal Supersymmetric extension of the Standard Model. The code is based on two existing programs HDECAY and SDECAY for the calculation of the decay widths and branching ratios of, respectively, the MSSM Higgs bosons and the SUSY particles, and calls a program for the calculation of the SUSY particle spectrum such as SuSpect. Including all important higher order effects, the package allows the consistent calculation of the MSSM particle spectrum and decays with the presently highest level of precision.

abstract

We address the question of dark matter in the context of gauge mediated supersymmetry breaking models. In contrast with mSUGRA scenarios, the messenger of the susy breaking to the visible sector can play an important role allowing a relic gravitino in the \(\sim \textrm {keV}\) to \(10 \textrm {MeV}\) mass range to account for the cold dark matter in the Universe.

abstract

Generic signatures of supersymmetry with \(R\)-parity conservation include those of single isolated muons or like-sign isolated dimuon pairs, accompanied with energetic jets and missing transverse energy. The ability of CMS to discover supersymmetry with these signals is estimated for 10 fb\(^{-1}\) of data collected with the inclusive single-muon and dimuon high-level-trigger paths. The selection criteria are optimized and the systematic effects are studied for a single low-mass benchmark point of the constrained MSSM with \(m_0 = 60\) GeV/\(c^2\), \(m_{1/2} = 250\) GeV/\(c^2\), \(\tan \beta =10\), \(A_0=0\) and \(\mu \gt 0\). Discovery contours in the (\(m_0\), \(m_{1/2}\)) plane are presented for integrated luminosities ranging from 1 to 100 fb\(^{-1}\).

abstract

We discuss an inclusive analysis strategy for SUSY searches in \(pp\) collisions at \(\sqrt {s}=14\) TeV with the CMS detector, where the missing transverse energy plus multijets canonical signature is used. Emphasis is put on methods to normalize the backgrounds using the data and on understanding the experimental systematic uncertainties. A 5\(\sigma \) excess can be observed with \(O(\rm {pb}^{-1})\) at a particular low mass SUSY point. The 5\(\sigma \) discovery reach contours in the mSUGRA parameter space for 1 and 10 fb\(^{-1}\) are obtained.