Experimental particle physics

Searches for “natural” supersymmetry (SUSY) scenarios are presented in which only neutralinos, charginos, and potentially also the top-quark superpartner (stop) are assumed to be accessible, and which result in multi-boson final states. These efforts rely on a novel and versatile method where by the narrow H → γγ resonance is used to identify events with a Higgs boson candidate, and to determine backgrounds. This provides a sufficiently clean search environment to largely overcome the small H → γγ branching fraction. First, a search is performed for stop pair production resulting in 2b2H. Events with two photons forming a Higgs boson candidate and at least two b-jets are selected and missing transverse energy is examined. Then, the diphoton components of a comprehensive search for electroweak production of neutralinos and charginos are presented, which may decay to Higgs and Z, bosons and undetected lightest SUSY particles (LSPs). This latter search is then reinterpreted in terms of chargino-neutralino pair production, leading to HW± states with MET. The searches are performed using 19.5 fb−1 of proton-proton collisions at √s = 8 TeV, recorded in the Compact Muon Solenoid (CMS) detector. No compelling evidence for new physics is found and 95% confidence limits are set.

In 2004, a combined system test was performed in the H8 beam line at the CERN SPS with a setup reproducing the geometry of sectors of the ATLAS Muon Spectrometer, formed by three stations of Monitored Drift Tubes (MDT). The full ATLAS analysis chai n was used to obtain the results presented in this paper. The basic design performances of the Muon Spectrometer were verified. The stability of MDT calibration constants, the alignment system using optical devices and high energy tracks, as well as the i ntrinsic sagitta resolution of the Muon Spectrometer were studied and found to agree with expectations. The reconstruction of muon tracks using the combined information from both the Inner Detector and the Muon Spectrometer are also presented.

Science from History to Future CONTENTS 1. INERTIA 2. Form of Intensity of the Moving Charge Electric Field is Asymmetrical. 3. Form of the Interference Field is Non-Linear 4. CORRECTED Maswell's equations 5. Corrected Newton´s Laws of Motion 6. Kinetic energy of a charge moving at the velocity of v has two different values: Kinetic energy against direction of motion as wave Tkin ad = mc2 [ln |1+v/c|- (v/c)/(1+v/c)] Kinetic energy in direction of motion as particle Tkin id = mc2 [ln|1-v/c|+ (v/c)/(1-v/c)] 7. Physics is Easy 8. Particles, Waves and Trends in Physics 9. Physics is Beautiful 10. Great Table of Elementary Particles 11. Movement Principles of the Fast-Spinning Bodies 12. Nuclear Fusion

This paper describes the data acquisition and high level trigger system of the ATLAS
experiment at the Large Hadron Collider at CERN, as deployed during Run 1. Data flow as well as
control, configuration and monitoring aspects are addressed. An overview of the functionality of
the system and of its performance is presented and design choices are discussed.

The production of Υ (1S), Υ (2S) and Υ (3S) mesons in proton-proton collisions at the centre-of-mass energy of √ s = 7 TeV is studied with the LHCb detector. The analysis is based on a data sample of 25 pb −1 collected at the Large Hadron Collider. The Υ mesons are reconstructed in the decay mode Υ → μ + μ − and the signal yields are extracted from a fit to the μ + μ − invariant mass distributions. The differential production cross-sections times dimuon branching fractions are measured as a function of the Υ transverse momentum p T and rapidity y, over the range p T < 15 GeV/c and 2.0 < y < 4.5. The cross-sections times branching fractions, integrated over these kinematic ranges, are measured to be σ pp → Υ (1S)X × B Υ (1S) → μ + μ − = 2.29 ± 0.01 ± 0.10 +0.19 −0.37 nb, σ pp → Υ (2S)X × B Υ (2S) → μ + μ − = 0.562 ± 0.007 ± 0.023 +0.048 −0.092 nb, σ pp → Υ (3S)X × B Υ (3S) → μ + μ − = 0.283 ± 0.005 ± 0.012 +0.025 −0.048 nb, where the first uncertainty is statistical, the second systematic and the third is due to the unknown polarisation of the three Υ states. 14.7 ± 1.3 ± 0.7 +0.3 −0.6 6.7 ± 0.9 ± 0.3 +0.1 −0.2 4.3 ± 1.0 ± 0.2 +0.1 −0.3 12-13 20.3 ± 2.1 ± 1.0 +1.9 −3.7

Weak scale supersymmetry, which is one of the best motivated and studied Standard Model extensions, predicts that every SM particle has a partner with different spin. Both supersymmetry and other extensions of the Standard Model predicts the existence of several Higgs bosons. This talk summarizes the searches for supersymmetric particles and for additional heavy Higgs bosons performed with the ATLAS experiments at the LHC, with emphasis on those targeting final states with tau leptons.

In this paper, we give an analytical description of the Halbach wiggler field, in view of its application in polarized beam focusing. In particular, we derive formulas describing its multipole components and the focal length of a cell. It turns out that, depending on the ratio between the spatial period of the magnetic field and gap length, the system can be considered as a magnetic mirror, then an almost pure sextupole, then an almost pure quadrupole. The formulas are found to describe fairly well the results of numerical simulations.