61,299 research outputs found
The Thermodynamic Potentials of Kerr-AdS Black Holes and their CFT Duals
String or M-theory in the background of Kerr-AdS black holes is thought to be
dual to the large n limit of certain conformal field theories on a rotating
sphere at finite temperature. The five dimensional black hole is associated to
N=4 supersymmetric Yang-Mills theory on a rotating three-sphere and the four
dimensional one to the superconformal field theory of coinciding M2 branes on a
rotating two-sphere. The thermodynamic potentials can be expanded in inverse
powers of the radius of the sphere. We compute the leading and subleading terms
of this expansion in the field theory at one loop and compare them to the
corresponding supergravity expressions. The ratios between these terms at weak
and strong coupling turns out not to depend on the rotation parameters in the
case of N=4 SYM. For the field theory living on one M2 brane we find a
subleading logarithmic term. No such term arises from the supergravity
calculation.Comment: 14 pages (harvmac b-mode), signs corrected, minor changes otherwis
On the graphical extraction of multipole mixing ratios of nuclear transitions
We propose a novel graphical method for determining the mixing ratios
{\delta} and their associated uncertainties for mixed nuclear transitions. It
incorporates the uncertainties both on both the measured and the theoretical
conversion coefficients. The accuracy of the method has been studied by
deriving the corresponding probability density function. The domains of
applicability of the method are carefully defined
Measurement of the Υ (1S) production cross-section in pp collisions at √s = 7 TeV in ATLAS
A measurement of the cross-section for Υ (1S)→μ^+μ^− production in proton–proton collisions at centre of mass energy of 7 TeV is presented. The cross-section is measured as a function of the Υ (1S) transverse momentum in two bins of rapidity, |y^(Υ(1S))| 4 GeV and pseudorapidity |η^μ| < 2.5 in order to reduce theoretical uncertainties on the acceptance, which depend on the poorly known polarisation. The results are based on an integrated luminosity of 1.13 pb^(−1), collected with the ATLAS detector at the
Large Hadron Collider. The cross-section measurement is compared to theoretical predictions: it agrees
to within a factor of two with a prediction based on the NRQCD model including colour-singlet and
colour-octet matrix elements as implemented in Pythia while it disagrees by up to a factor of ten with
the next-to-leading order prediction based on the colour-singlet model
Search for pair production of first or second generation leptoquarks in proton-proton collisions at √s = 7 TeV using the ATLAS detector at the LHC
This paper describes searches for the pair production of first or second generation scalar leptoquarks using 35 pb^(-1) of proton-proton collision data recorded by the ATLAS detector at √s=7 TeV. Leptoquarks are searched in events with two oppositely-charged muons or electrons and at least two jets, and in events with one muon or electron, missing transverse momentum and at least two jets. After event selection, the observed yields are consistent with the predicted backgrounds. Leptoquark production is excluded at the 95% CL for masses M_(LQ)<376 (319) GeV and M_(LQ)<422 (362) GeV for first and second generation scalar leptoquarks, respectively, when assuming the branching fraction of a leptoquark to a charged lepton is equal to 1.0 (0.5)
Limits on the production of the standard model Higgs boson in pp collisions at √s = 7 TeV with the ATLAS detector
A search for the Standard Model Higgs boson at the Large Hadron Collider (LHC) running at a centre-of-mass energy of 7 TeV is reported, based on a total integrated luminosity of up to 40 pb^(−1) collected by the ATLAS detector in 2010. Several Higgs boson decay channels: H→γγ, H→ZZ^((∗))→ℓℓℓℓ, H→ZZ→ℓℓνν, H→ZZ→ℓℓqq, H→WW^((∗))→ℓνℓν and H→WW→ℓνqq (ℓ is e, μ) are combined in a mass range from 110 GeV to 600 GeV. The highest sensitivity is achieved in the mass range between 160 GeV and 170 GeV, where the expected 95% CL exclusion sensitivity is at Higgs boson production cross sections 2.3 times the Standard Model prediction. Upper limits on the cross section for its production are determined. Models with a fourth generation of heavy leptons and quarks with Standard Model-like couplings to the Higgs boson are also investigated and are excluded at 95% CL for a Higgs boson mass in the range from 140 GeV to 185 GeV
Exact Wave Functions for Generalized Harmonic Oscillators
We transform the time-dependent Schroedinger equation for the most general
variable quadratic Hamiltonians into a standard autonomous form. As a result,
the time-evolution of exact wave functions of generalized harmonic oscillators
is determined in terms of solutions of certain Ermakov and Riccati-type
systems. In addition, we show that the classical Arnold transformation is
naturally connected with Ehrenfest's theorem for generalized harmonic
oscillators.Comment: 10 pages, no figure
Flipped Angles and Phases: A Systematic Study
We discuss systematically the fermion mass and mixing matrices in a generic
\linebreak field-theoretical flipped model, with particular
applications to neutrino and baryon number-changing physics. We demonstrate
that the different quark flavour branching ratios in proton decay are related
to the Cabibbo-Kobayashi-Maskawa angles, whereas the lepton flavour branching
ratios are undetermined. The light neutrino mixing angles observable via
oscillation effects are related to the heavy conjugate (right-handed) neutrino
mass matrix, which also plays a key role in cosmological baryogenesis. The
ratios of neutrino and charged lepton decay modes in baryon decay may also be
related to neutrino oscillation parameters. Plausible Ans\"atze for the
generation structure of coupling matrices motivate additional relations between
physical observables, and yield a satisfactory baryon asymmetry.Comment: 13 pages, no figures, latex (twice), CERN-TH.6842/93, UMN-TH-1130/93,
CTP-TAMU-11/9
Measurement of the differential cross-sections of inclusive, prompt and non-prompt J/ψ production in proton–proton collisions at √s = 7 TeV
The inclusive J/ψ production cross-section and fraction of J/ψ mesons produced in B-hadron decays are measured in proton–proton collisions at √s = 7 TeV with the ATLAS detector at the LHC, as a function of the transverse momentum and rapidity of the J/ψ, using 2.3 pb^(−1) of integrated luminosity. The cross-section is measured from a minimum pT of 1 GeV to a maximum of 70 GeV and for rapidities within |y|<2.4 giving the widest reach of any measurement of J/ψ production to date. The differential production cross-sections of prompt and non-prompt J/ψ are separately determined and are compared to Colour Singlet NNLO^★, filled, Colour Evaporation Model, and FONLL predictions
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