Search

A design is presented of a laboratory experiment that could test the suitability of relativistic gravity for propulsion of spacecraft to relativistic speeds. An exact time-dependent solution of Einstein’s gravitational field equation confirms that even the weak field of a mass moving at relativistic speeds could serve as a driver to accelerate a much lighter payload from rest to a good fraction of the speed of light. The time-dependent field of ultrarelativistic particles in a collider ring is calculated. An experiment is proposed as the first test of the predictions of general relativity in the ultrarelativistic limit by measuring the repulsive gravitational field of bunches of protons in the Large Hadron Collider (LHC). The estimated ‘antigravity beam’ signal strength at a resonant detector of each proton bunch is 3 nm/s2 for 2 ns during each revolution of the LHC. This experiment can be performed off-line, without interfering with the normal operations of the LHC. [ABSTRACT FROM AUTHOR]

The first LHC measurement on ultra-peripheral heavy-ion collisions was carried out with the ALICE experiment. In this paper, ALICE results on exclusive J/ψ studies in Pb-Pb collisions at [formula], in the rapidity region -3.6 < y < -2.6, are given. The coherent J/ψ cross section was found to be dσcohJ/ψ/dy = 1.00 ± 0.18 (stat)+0.24-0.26 (syst) mb. These studies favour theoretical models that include strong modifications to the nuclear gluon density, also known as nuclear gluon shadowing. [ABSTRACT FROM AUTHOR]

The Electromagnetic Calorimeter of the CMS experiment at the LHC includes about 76000 lead tungstate (PbWO4) scintillating crystals. The detector properties must be continuously monitored in order to ensure the extreme stability and precision required. This leads to a very large volume of non-event data to be accessed continuously by shifters, experts, automatic monitoring tasks, detector configuration for trigger and data acquisition systems and offline data reconstruction programs. This paper describes the measurements taken by the Detector Control System, the calibrations, the data handling strategy and the workflow as well as the architecture of the configuration and conditions databases and the web interface to access the data. An overview is given on the experience with detector commissioning, which have allowed a system test in realistic run conditions. [ABSTRACT FROM AUTHOR]

This is my contribution to the commemoration of my great friend Giuseppe ('Beppe') Nardulli who left us in June 2008. [ABSTRACT FROM AUTHOR]

This paper addresses the control optimization of a 4.5 K refrigerator used in the cryogenic system of the Large Hadron Collider (LHC) at CERN. First, the compressor station with the cold-box have been modeled and simulated under PROCOS (Process and Control Simulator), a simulation environment developed at CERN. Next, an appropriate parameter identification has been performed on the simulator to obtain a simplified model of the system in order to design an Internal Model Control (IMC) enhancing the regulation of the high pressure. Finally, a floating high pressure control is proposed using a cascade control to reduce operational costs. [ABSTRACT FROM AUTHOR]

Linac4 is a 160 MeV linear accelerator which will inject negative hydrogen ions (H-) into CERN's Proton Synchrotron Booster, a required upgrade to improve the beam brightness in the LHC injector chain. A volume production RF ion source, based on the design of the DESY RF source was implemented, but showed considerable electron dump ablation during operation at 45 keV beam energy. To reduce the electron beam power density in the dump, a magnetized Einzel lens is designed that reduces the beam energy to 10 keV before permanentmagnets dump the electrons on a tungsten surface. Presented in this paper are simulations of the design using IBSimu, the tunable range of parameters depending on the extracted H- and electron current, as well as details of the implementation, the choice of pulsed power converters and the electrode alignment system. In addition, simulations of proton extraction from this source will be shown. [ABSTRACT FROM AUTHOR]

The Large Hadron Collider forward (LHCf) experiment has performed measurements of the neutral particles emitted to the very forward region of proton-proton collisions at LHC. This experiment is designed to explore very forward interaction at very high energy, which is relevant to interpretation of the data from cosmic-ray experiments. LHCf detector is well optimized to measure photons in the multi-TeV energy range, and to reconstruct neutral pions with two photons. It can also measure neutrons. The data acquisitions at 0.9 TeV and 7 TeV were completed in 2010. In this paper, single photon energy spectra obtained at 0.9 TeV and transverse energy spectra of neutral pions obtained at 7 TeV will be presented. The results are compared with expectations by hadronic interaction models used for air-shower simulations. We found none of these models agree with the obtained data in the photon energy spectra, while EPOS shows a good agreement in the transverse energy spectra of neural pions. Impacts on cosmic-ray and QCD physics are also discussed. [ABSTRACT FROM AUTHOR]

The Accelerator Project for Upgrade of LHC (APUL) is a U.S. project participating in and contributing to CERN's Large Hadron Collider (LHC) upgrade program. FermiNational Accelerator Laboratory in collaboration with Brookhaven National Laboratorywas developing sub-systems for the upgrade of the LHC final focus magnet systems. Partof the upgrade called for various lengths of superconducting power transmission linesknown as Superconducting (SC) Links which were up to 100 m long. The SC Linkelectrically connects the current leads in the Distribution Feed Boxes to the interactionregion magnets. The SC Link is an extension of the magnet bus housed within a cryostat.The present concept for the bus consists of 22 power cables, 4 × 13 kA, 2 × 7 kA, 8 × 2.5kA and 8 × 0.6 kA bundled into one bus. Different cable and strand possibilities were considered for the bus design including Rutherford cable. The Rutherford cable bus designpotentially would have required splices at each sharp elbow in the SC Link. The advantage of the round bus design is that splices are only required at each end of the bus duringinstallation at CERN. The round bus is very flexible and is suitable for pulling through thecryostat. Development of the round bus prototype and of 2 splice designs is described in this paper. Magnetic analysis and mechanical test results of the 13 kA cable and splices are presented. [ABSTRACT FROM AUTHOR]

Fermilab is collaborating with Lawrence Berkeley National Laboratory (LBNL) and Brookhaven National Laboratory (BNL) within the US-LHC Accelerator Research Project (US-LARP collaboration) to develop a large-aperture Nb3SN superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade. Several two-layer quadrupole models of the 1-meter and 3.4-meter length with 90 mm apertures have been fabricated and tested by the US-LARP collaboration. High-Jc Nb3SN RRP-54/61 strand was used for nearly all models. Large flux jumps typical for this strand, due to the large sub-element diameter, limited magnet quench performance at temperatures below 2.5-3K. This paper summarizes the fabrication and test by Fermilab of LQM01, a long quadrupole coil test structure (quadrupole mirror) with the first 3.4 m quadrupole coil made of more stable RRP-114/127 strand. The coil and structure are fully instrumented with voltage taps, full bridge strain gauges and strip heaters to monitor preload, thermal properties and quench behavior. Measurements during fabrication are reported, including preload during the yoke welding process. Testing is done at 4.5 K, 1.9 K and a range of intermediate temperatures. The test results include magnet strain and quench performance during training, as well as quench studies of current ramp rate and temperature dependence from 1.9 K to 4.5 K. [ABSTRACT FROM AUTHOR]

Taus, being the heaviest of the leptons, constitute an important tool for searches for new physics at the LHC. Higgs boson couples to mass leading to a significant branching ratio of about 10% for low mass Higgs decaying to tau pairs. Taus become even more important in the minimal supersymmetric extension of the Standard model where the neutral Higgs production is enhanced and the presence of two Higgs doublets results in prediction of additional charged Higgs bosons that may preferentially decay to final states with tau leptons. This paper describes a search for Higgs bosons decaying to di-tau pairs and a search for charged Higgs bosons decaying to taus and neutrinos using about 1 fb-1 of data collected with the CMS detector in 2011. [ABSTRACT FROM AUTHOR]

A Large Ion Collider Experiment (ALICE) is one of the four experiments at the Large Hadron Collider (LHC), and it is dedicated to the study of ultra-relativistic heavy-ion collisions, with the goal of investigating the properties of the high-density state of QCD matter produced in such events. The first Pb-Pb collisions at a centre of mass energy of [formula] TeV per nucleon pair were delivered by LHC in November 2010. In Pb-Pb collisions heavy quarks are regarded as sensitive probes of the interaction dynamics between the parton and the medium produced in such collisions as they are produced on a very short time scale in the initial hard scattering processes and they follow all the evolution of the medium. At the energies available at the LHC charm is produced with large cross section and therefore it is possible to measure its production with good statistical precision. The study of open charm hadrons such as D+, D0, D*+, Ds and Λc in heavy ion collision is of particular interest because it can provide significant insight on the properties of the medium. Proton-proton collision data, that are being recorded at an energy of [formula] TeV since March 2010 provide an essential reference for these studies and allow to test perturbative QCD calculations in an unexplored energy domain. In this paper the analysis of D-meson production, carried out through a study of the hadronic decay channels in Pb-Pb collisions, will be presented in detail. The results for the reconstruction of D0, D+, D*+, and Ds hadrons at central rapidity will be shown along with the first results for the measurement of the D0 and D+ nuclear modification factor and prospects for azimuthal anisotropy studies. [ABSTRACT FROM AUTHOR]

ALICE (A Large Ion Collider Experiment) is the dedicated heavy-ion experiment at the LHC. In fall 2010, Pb-Pb collisions were recorded at a center-of-mass energy of 2.76 TeV per nucleon pair, about 14 times higher than the energy achieved in A-A collisions at RHIC. The study of the produced hot and dense matter with an unprecedented energy density allows the characterization of the quark-gluon plasma, the deconfined state of quarks and gluons, predicted by QCD. The study of in-medium partonic energy loss allows insights into the density of the medium and the energy-loss mechanisms. This paper presents results based on inclusive spectra as well as two and more-particle correlations of charged particles. These are well suited to assess in-medium effects, ranging from the suppression of particles (RAA) and away-side jets (IAA) at high pT to longrange phenomena attributed to collective effects like the ridge at low pT. The analysis is discussed and the results are presented in the context of earlier RHIC measurements where appropriate. [ABSTRACT FROM AUTHOR]

Analysis techniques in LHCf are presented, in which all techniques are required to have a high resolution and efficiency in order to overcome the severe situation, small lateral aperture and longitudinally short length of the detector. In this paper, methods for reconstructing an energy of electromagnetic shower are discussed following the data flow of measured data and Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

We give a brief description of the purpose of the LHCf experiment, detectors and their performance, and what has been done in the first year experiment. A short summary of results at [formula] is given although the energy is not an 'intrinsic' LHC energy. Since detailed results at [formula] will appear soon elsewhere, here we limit ourselves to giving also a brief account of what will come in that paper. [ABSTRACT FROM AUTHOR]

The ALICE experiment at the CERN's Large Hadron Collider allows the study of charmonium production in both e+e- and μ+μ- decay channels. In this paper, the first results obtained from reconstructing J/ψ mesons in proton-proton interactions at s = 7 TeV are discussed. The present plans for quarkonia analyses are also mentioned. [ABSTRACT FROM AUTHOR]

The superconducting magnets of the Large Hadron Collider (LHC) distributed over eight sectors of 3.3-km long are cooled at 1.9 K in pressurized superfluid helium. During the commissioning campaign of the sectors in 2008, cold standby periods at nominal operating temperature have allowed to measure the overall static heat inleaks reaching the magnet cold masses at 1.9 K by enthalpy balance in steady-state operation. In addition, during electrical powering of the different magnet circuits, helium II calorimetry based on precision thermometry has been implemented to assess with an accuracy of 100 mW/m the additional heat loads due to resistive heating and to detect possible abnormal heat dissipation during powering. This paper describes the method applied to perform these measurements, compares the results with the expected specified values and discusses the impact of the measured values on cryo-plant tuning and operational margins. [ABSTRACT FROM AUTHOR]

The insertion regions located around the four interaction points of the Large Hadron Collider (LHC) are mainly composed of the low-β triplets, the separation dipoles and their respective electrical feed-boxes (DFBX). The low-β triplets are Nb-Ti superconductor quadrupole magnets, which operate at 215 T/m in superfluid helium at a temperature of 1.9 K. The commissioning and the first operation of these components have been performed. The thermo-mechanical behavior of the low-βtriplets and DFBX were studied. Cooling and control systems were tuned to optimize the cryogenic operation of the insertion regions. Hardware commissioning also permitted to test the system response. This paper summarizes the performance results and the lessons learned. [ABSTRACT FROM AUTHOR]

The US LHC Accelerator Research Program (LARP) is a collaboration between four US laboratories (BNL, FNAL, LBNL, and SLAC) aimed at contributing to the commissioning and operation of the LHC and conducting R&D on its luminosity upgrade. Within LARP, the Magnet Program’s main goal is to demonstrate that Nb3Sn superconducting magnets are a viable option for a future upgrade of the LHC Interaction Regions. Over the past four years, LARP has successfully fabricated and tested several R&D magnets: 1) the subscale quadrupole magnet SQ, to perform technology studies with 300 mm long racetrack coils, 2) the technology quadrupole TQ, to investigate support structure behavior with 1 m long cos 2θ coils, and 3) the long racetrack magnet LR, to test 3.6 m long racetrack coils. The next milestone consists in the fabrication and test of the 3.7 m long quadrupole magnet LQ, with the goal of demonstrating that Nb3Sn technology is mature for use in high energy accelerators. After an overview of design features and test result of the LARP magnets fabricated so far, this paper focuses on the status of the fabrication of LQ: we describe the production of the 3.4 m long cos 2θ coils, and the of the qualification support structure. Finally, the status of the development of the next 1 m long model HQ, conceived to explore stress and field limits of Nb3Sn superconducting, magnets, is presented. [ABSTRACT FROM AUTHOR]

Fermilab is developing Nb3Sn quadrupole magnets for the planned upgrade of interaction regions of the Large Hadron Collider (LHC). Two distinctly different approaches have been employed, one using quadrupole-symmetric and one using dipole-symmetric collar laminations. This paper describes the design features of both collar types, collaring techniques for brittle Nb3Sn coils, and compares the advantages and disadvantages of the two approaches. Results of mechanical analysis for quadrupoles based on dipole-type and quadrupole-type collars are presented. Magnet construction issues and test results are reported. Test results include coil and component strain measurements during construction. Plans for the completion and test of the first dipole-symmetric assembly are described. [ABSTRACT FROM AUTHOR]

In November 2010 the ALICE experiment at CERN has collected the first Pb-Pb collisions at [formula] TeV produced by the LHC. A first characterization of the hot and dense state of matter produced in this new energy domain became available shortly after the run. In this paper we present the results on charged-particle multiplicity, Bose-Einstein correlations, elliptic flow and their dependence on the collision centrality. Results from first measurements of strange and identified particle production and suppression of high-momentum hadrons with respect to pp collisions are also reported. [ABSTRACT FROM AUTHOR]

In this paper we study the charged particle and transverse energy production mechanism from AGS to LHC energies in the framework of nucleon and quark participants as well. A universal function which is a combination of logarithmic and power-law, describes the charged particle and transverse energy production both at nucleon and quark participant level quite well for the whole range of collision energies. We give the predictions for dNch/dη, dET/dη and the barometric observable, ET/Nch for Pb+Pb collisions at [formula]. [ABSTRACT FROM AUTHOR]

This was the first symposium on computing in experimental high energy physics to be held during the ICCMSE conference. The symposium attracted 21 papers on a number of topics relevant for present day high energy physics experiments. [ABSTRACT FROM AUTHOR]

Results on factorization breaking in soft and hard hadron-hadron collisions, photo-production and deep inelastic scattering exhibit a universal behavior in a renormalization model where diffraction is mediated by a saturated colorless exchange with vacuum quantum numbers. Using this model, diffractive and total cross sections are predicted for LHC energies. [ABSTRACT FROM AUTHOR]

We discuss two topical problems of diffraction dissociation at the LHC, namely the role of the background and the elastic contribution. [ABSTRACT FROM AUTHOR]

We present first results from the ATLAS Zero Degree Calorimeters (ZDC) based on 7 TeV pp collision data recorded in 2010. The ZDC coverage of ±∼350 μrad about the forward direction makes possible the measurement of neutral particles (primarily π0's and neutrons) over the kinematic region xF>=0.1 and out to pT<=1.2 GeV/c at large xF. The ATLAS ZDC is unique in that it provides a complete image of both electromagnetic and hadronic showers. This is illustrated with the reconstruction of π0's with energies of 0.7-3.5 TeV. We also discuss the waveform reconstruction algorithm which has allowed good time-of-flight resolution on leading neutrons emerging from the collisions despite the sparse (40 MHz) sampling of the calorimeter signals used. [ABSTRACT FROM AUTHOR]

The Large Hadron Collider (LHC) is presently undergoing beam commissioning in preparation for physics running in 2010 at a center of mass energy of 7 TeV. I will briefly describe the hadron physics capabilities of the ATLAS, CMS, and LHCb detectors, their performance with cosmic ray and early collision data, as well as their plans for physics with the first data. [ABSTRACT FROM AUTHOR]

Extra dimensions provide a very useful tool in addressing a number of the fundamental problems faced by the Standard Model. The following provides a very basic introduction to this very broad subject area as given at the VIII School of the Gravitational and Mathematical Physics Division of the Mexican Physical Society in December 2009. Some prospects for extra dimensional searches at the 7 TeV LHC with ∼1 fb-1 of integrated luminosity are provided. [ABSTRACT FROM AUTHOR]

The production of high-pT b-jets at the Large Hadron Collider LHC is an important process probing perturbative QCD at next-to-leading order. High-pT b-jets also form a significant background to many Standard Model and Beyond the Standard Model physics channels at the LHC. Measurements of the inclusive differential and dijet cross section of b-jets in proton-proton collisions at [Square_Root]s = 7 TeV, using data collected with the ATLAS experiment corresponding to an integrated luminosity of 3 pb-1 is presented. These results are compared to NLO QCD predictions. [ABSTRACT FROM AUTHOR]

We have discussed single and central diffractive production of cc pairs in the Ingelman-Schlein model. In these calculations we have included diffractive parton distributions obtained by the H1 collaboration at HERA and absorption effects neglected in some early calculations in the literature. The absorption effects which are responsible for the naive Regge factorization breaking cause that the cross section for diffractive processes is much smaller than that for the fully inclusive case, but could be measured at RHIC and LHC by imposing special condition on rapidity gaps. We discuss also different approaches to diffractive production of heavy quark/antiquark [1, 2, 3]. The particular mechanism is similar to the diffractive dissociation of virtual photons into quarks, which drives diffractive deep inelastic production of charm in the low-mass diffraction, or large β-region. [ABSTRACT FROM AUTHOR]

In the framework of the kT-factorization approach, the production of prompt photons in association with a heavy (charm or beauty) quarks at high energies is studied. The consideration is based on the O(αα2s) off-shell amplitudes of gluon-gluon fusion and quark-(anti)quark interaction subprocesses. The unintegrated parton densities in a proton are determined using the Kimber-Martin-Ryskin prescription. Our numerical predictions are compared with the D0 and CDF experimental data. Also we extend our results to LHC energies. [ABSTRACT FROM AUTHOR]

We report on charm production at LHC. The production of single cc pairs is calculated in the kt-factorization approachwith different unintegrated gluon distributions. Examples of transverse momentum distributions for charmed mesons are presented and compared to recent experimental results from LHC. Some missing strength is observed for most of UGDFs. Furthermore we discuss production of two cc pairs within double-parton scattering (DPS) and single-parton scattering (SPS) mechanisms. Surprisingly large cross sections, comparable to single cc pair production are predicted. We discuss first experimental results from LHCb collaboration on production of pairs of D mesons of the same flavour. [ABSTRACT FROM AUTHOR]

We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given. [ABSTRACT FROM AUTHOR]

We review our pre-LHC predictions of the total, elastic, total-inelastic, and diffractive components of proton-proton cross sections at high energies, expressed in the form of unitarized expressions based on a special parton-model approach to diffraction employing inclusive proton parton distribution functions and QCD color factors and compare with recent LHC results. [ABSTRACT FROM AUTHOR]

Diphoton events at the LHC can provide clean signals of heavy neutral quantum states predicted by New Physics models. These non-standard particles would manifest themselves by s-channel peaks in inclusive distributions in the diphoton invariant mass. Once discovered, the quantum numbers of such a diphoton resonance need to be determined in order to identify the associated non-standard physics, in the first place the spin by an angular analysis of the events. We here discuss this problem by comparing, as competing sources of a diphoton resonance, the spin-2 Randall-Sundrum graviton excitation and a spin-0 scalar exchange, by means of a specific angular-integrated asymmetry predicted theoretically at next-to-leading order in QCD. For the LHC with nominal energy of 14 TeV and integrated luminosity 100 fb-1, we find that graviton exchange could be discriminated against the scalar one with same mass MR and events rate, up to MR≃3.2TeV. [ABSTRACT FROM AUTHOR]

The Inner Tracking System of the ALICE experiment plays a crucial role in heavy flavour production measurements at central rapidity in Pb-Pb collisions thanks to its precise tracking and vertexing capabilities in a high-multiplicity environment. In view of the future luminosity increase at LHC, the ALICE experiment is developing an upgrade startegy where a new, more performant ITS is being proposed. Improving the tracking and particle identification performances, the resolution on the secondary vertices in the low momentum region as well as the read-out capabilities, the ITS will make new important measurements in the charm and beauty sector accessible in central heavy-ion collisions: the Λc baryon, B mesons and the total charm production cross section. In these proceeedings both the performances of a new ITS and some new accessible measurements of the heavy flavour physics in ALICE will be discussed. [ABSTRACT FROM AUTHOR]

We report on recent investigations of the underlying event in pp collisions at the LHC. The underlying event activity has been studied in Drell-Yan processes, using the jet area method and at forward rapidity. Strangeness production in the underlying event has been measured. [ABSTRACT FROM AUTHOR]

We discuss the case of the diffractive Higgs production at LHC. Aim of this talk is to propose the method of using Fracture Functions as an alternative to the ones already present in the literature. We discuss some of the questions involved and the main related issues. [ABSTRACT FROM AUTHOR]

We discuss the theoretical and experimental details of two of the main results obtained by LHCb with the 2011 data, namely the measurement of the mixing-induced CP-violation in the decay Bs0→J/ψ[lowercase_phi_synonym] and the upper limits on the decays B(s)0→μ+μ-. Then we describe the possible strategies to obtain new constraints on two different New Physics models in the light of these results. [ABSTRACT FROM AUTHOR]

In this Sixth International School on Field Theory and Gravitation, I was invited to give this talk to the students and researchers of Field Theory mainly about LHC - The Large Hadron Collider and results. I will try to summarize the main daily life of the high energy physics and give an idea about the experiments and the expectations for the near future. I will comment the present results and the prospects to LHC/CMS. [ABSTRACT FROM AUTHOR]

Conventional SO(10) models involve more than one scale for a complete breaking of the GUT symmetry requiring further assumptions on the VEVs of the Higgs fields that enter in the breaking to achieve viable models. Recent works where the breaking can be accomplished at one scale are discussed. These include models with just a pair of [formula] of Higgs fields. Further extensions of this idea utilizing [formula] of Higgs representations allow both the breaking at one scale, as well as accomplish a natural doublet-triplet splitting via the missing partner mechanism. More generally, we discuss the connection of high scale models to low energy physics in the context of supergravity grand unification. Here we discuss a natural solution to the little hierarchy problem and also discuss the implications of the LHC data for supersymmetry. It is shown that the LHC data implies that most of the parameter space of supergravity models consistent with the data lie on the Hyperbolic Branch of radiative breaking of the electroweak symmetry and more specifically on the Focal Surface of the Hyperbolic Branch. A discussion is also given of the implications of recent LHC data on the Higgs boson mass for the discovery of supersymmetry and for the search for dark matter. [ABSTRACT FROM AUTHOR]

We employ third family Yukawa unification, predicted by simple supersymmetric SO(10) models, to estimate the lightest MSSM Higgs boson mass. For μ > 0 (or μ < 0) and mt = 173.1GeV, the Higgs mass is estimated to lie close to 123-124 GeV. The theoretical uncertainty in this estimate is ±3 GeV. We highlight some LHC testable benchmark points which also display the presence of neutralino-stau coannihilation channel. [ABSTRACT FROM AUTHOR]

The ATLAS and CMS collaborations recently reported indication of a Higgs boson around 125GeV. If we add extra vector-like quarks to the MSSM, such a relatively heavy Higgs can be naturally realized in the GMSB framework, simultaneously explaining the muon g - 2 anomaly. I will discuss LHC prospect of this attractive model. [ABSTRACT FROM AUTHOR]

A make a qualitative study of the KT effect in the Higgs associative production with a W vector boson at the LHC. The kinematics are presented and the generalized form of the cross section is obtained. [ABSTRACT FROM AUTHOR]

The helecity amplitudes of the subprocess gg → γγ via scalar unparticles intermediate states are calculated. The differential cross section is compared to that of the standard model. Phenomenological implications are also discussed. [ABSTRACT FROM AUTHOR]

The contribution of the pure NCG forbidden subprocess gg → ZHis calculated. It is shown that the cross section becomes important at the LHC energies and depends strongly on the choice of the noncommutativity parameter. Because of the gluons luminosity inside the proton, it becomes comparable to that of the commutative standard model subprocess qq ZHfor reasonable values of the NCG parameter. [ABSTRACT FROM AUTHOR]

A pure NCG gluon fusion contribution to the Higgs production at large hadron colliders is discussed. It is shown that the NCG results become relevant at very high energies. This can be a good signal for the space-time non commutativity events. [ABSTRACT FROM AUTHOR]

Radiation resistant superconducting magnets are required for high intensity particle accelerators and associated secondary particle beamlines, such as the LHC upgrade and the COMET experiment at J-PARC. Expected neutron fluence on the superconducting coils reaches 1021 n/m2 or higher, therefore the magnet should be designed taking into account the irradiation effects. Irradiation tests for superconducting magnet materials have been carried out using reactor neutrons at Kyoto Univ. Research Reactor Institute. As a first step of the experiment, aluminum alloy stabilizer for superconducting cable was exposed to the reactor neutrons at low temperature and the resistance has been measured in situ during neutron exposure. After the irradiation at 12 K-15 K, the sample resistance increase was proportional to the integrated neutron fluence, and reached almost double for a fast-neutron fluence of 2.3×1020 n/m2 (>0.1 MeV). It is also confirmed that the induced resistance is fully recovered by thermal cycling to room temperature. Details of the irradiation test and the prospects are described. [ABSTRACT FROM AUTHOR]

The operation of the Large Hadron Collider superconducting magnets for current and high luminosity future applications relies on the cooling provided by helium-permeable cable insulations. These insulations take advantage of a He II micro-channels network constituting an extremely efficient path for heat extraction. In order to provide a fundamental understanding of the underlying thermal mechanisms, an experimental setup was built to investigate heat transport through single He II channels typical of the superconducting cable insulation network, where deviation from the macro-scale theory can appear. Micro-fabrication techniques were exploited to etch the channels down to a depth of ~ 16 ìm. The heat transport properties were measured in static pressurized He II and analyzed in terms of the laminar and turbulent He II laws, as well as in terms of the critical heat flux between the two regions. [ABSTRACT FROM AUTHOR]

The LHeC (Large Hadron electron Collider) is a proposed future colliding beam facility for lepton-nucleon scattering particle physics at CERN. A new 60 GeV electron accelerator will be added to the existing 27 km circumference 7 TeV LHC for collisions of electrons with protons and heavy ions. Two basic design options are being pursued. The first is a circular accelerator housed in the existing LHC tunnel which is referred to as the "Ring-Ring" version. Low field normal conducting magnets guide the particle beam while superconducting (SC) RF cavities cooled to 2 K are installed at two opposite locations at the LHC tunnel to accelerate the beams. For this version in addition a 10 GeV re-circulating SC injector will be installed. In total four refrigerators with cooling capacities between 1.2 kW and 3 kW @ 4.5 K are needed. The second option, referred to as the "Linac-Ring" version consists of a race-track re-circulating energyrecovery type machine with two 1 km long straight acceleration sections. The 944 high field 2 K SC cavities dissipate 30 kW at CW operation. Eight 10 kW @ 4.5 K refrigerators are proposed. The particle detector contains a combined SC solenoid and dipole forming the cold mass and an independent liquid argon calorimeter. Cooling is done with two individual small sized cryoplants; a 4.5 K helium, and a 87 K liquid nitrogen plant. [ABSTRACT FROM AUTHOR]

The medium-modifications of processes characterized by the presence of a hard scale provide the most diverse tools to characterize the properties of the matter created in high-energy nuclear collisions. Indeed, jet quenching, the suppression of particles produced at high transverse momentum, has been established at RHIC almost a decade ago as one of the main tools in heavy-ion collisions. The melting of quarkonia is expected to provide also information about the temperature and the properties of the produced medium. The beginning of the LHC era for hot QCD studies starts with the first nuclear beams in 2010. The amount of information produced by this first run is overwhelming: The three experiments with nuclear program (ALICE, ATLAS and CMS) have provide new results in basically all subjects considered in previous experiments and have also shown the potential to make nuclear collisions at the TeV scale for the first time. I will review what the results from both RHIC and LHC imply for our understanding of hot and dense QCD matter from a theorists' perspective and how these new results change some of the concepts we developed in the last years. Particular attention is devoted to the case of jets, as the first data recently published from the LHC and the limitations of previous approaches call for a new theory of jets in a medium. [ABSTRACT FROM AUTHOR]