122 research outputs found
Higgs production and decay: Analytic results at next-to-leading order QCD
The virtual two-loop corrections for Higgs production in gluon fusion are
calculated analytically in QCD for arbitrary Higgs and quark masses. Both
scalar and pseudo-scalar Higgs bosons are considered. The results are obtained
by expanding the known one-dimensional integral representation in terms of
m_H/m_q, and matching it with a suitably chosen ansatz of Harmonic
Polylogarithms. This ansatz is motivated by the known analytic result for the
Higgs decay rate into two photons. The method also allows us to check this
result and to extend it to the pseudo-scalar decay rate.Comment: LaTeX, 16 pages, 5 figures (8 eps-files
Measurement of W Polarisation at LEP
The three different helicity states of W bosons produced in the reaction e+
e- -> W+ W- -> l nu q q~ at LEP are studied using leptonic and hadronic W
decays. Data at centre-of-mass energies \sqrt s = 183-209 GeV are used to
measure the polarisation of W bosons, and its dependence on the W boson
production angle. The fraction of longitudinally polarised W bosons is measured
to be 0.218 \pm 0.027 \pm 0.016 where the first uncertainty is statistical and
the second systematic, in agreement with the Standard Model expectation
Branching fraction and CP asymmetry of the decays B+→K0Sπ+ and B+→K0SK+
An analysis of B+ → K0
Sπ+ and B+ → K0
S K+ decays is performed with the LHCb experiment. The pp
collision data used correspond to integrated luminosities of 1 fb−1 and 2 fb−1 collected at centre-ofmass
energies of
√
s = 7 TeV and
√
s = 8 TeV, respectively. The ratio of branching fractions and the
direct CP asymmetries are measured to be B(B+ → K0
S K+
)/B(B+ → K0
Sπ+
) = 0.064 ± 0.009 (stat.) ±
0.004 (syst.), ACP(B+ → K0
Sπ+
) = −0.022 ± 0.025 (stat.) ± 0.010 (syst.) and ACP(B+ → K0
S K+
) =
−0.21 ± 0.14 (stat.) ± 0.01 (syst.). The data sample taken at
√
s = 7 TeV is used to search for
B+
c
→ K0
S K+ decays and results in the upper limit ( fc · B(B+
c
→ K0
S K+
))/( fu · B(B+ → K0
Sπ+
)) <
5.8 × 10−2 at 90% confidence level, where fc and fu denote the hadronisation fractions of a ¯b
quark
into a B+
c or a B+ meson, respectively
Measurement of the branching fraction
The branching fraction is measured in a data sample
corresponding to 0.41 of integrated luminosity collected with the LHCb
detector at the LHC. This channel is sensitive to the penguin contributions
affecting the sin2 measurement from The
time-integrated branching fraction is measured to be . This is the most precise measurement to
date
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
Measurement of the mixing-induced CP-violating phase phi_s in Bs decays is of
prime importance in probing new physics. Here 7421 +/- 105 signal events from
the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp
collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A
time-dependent fit to the data yields a value of
phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard
Model expectation. No evidence of direct CP violation is found.Comment: 15 pages, 10 figures; minor revisions on May 23, 201
Inelastic photoproduction of J/Psi mesons at HERA
An analysis of inelastic photoproduction of J/Psi mesons is presented using data collected at the ep collider HERA corresponding to an integrated luminosity of above 80pb-1. Differential and double differential cross sections are measured in a wide kinematic region: 6
Determination of gamma and-2 beta(s) from charmless two-body decays of beauty mesons
Using the latest LHCb measurements of time-dependent CP violation in the
B^0_s -> K^+K^- decay, a U-spin relation between the decay amplitudes of B^0_s
-> K^+K^- and B^0 -> \pi^+\pi^- decay processes allows constraints to be placed
on the angle gamma of the unitarity triangle and on the B^0_s mixing phase
-2\beta_s. Results from an extended approach, which uses additional inputs on
B^0 -> \pi^0\pi^0 and B^+ -> \pi^+\pi^0 decays from other experiments and
exploits isospin symmetry, are also presented. The dependence of the results on
the maximum allowed amount of U-spin breaking is studied. At 68% probability,
the value \gamma = ( 63.5 +7.2 -6.7 ) degrees modulo 180 degrees is determined.
In an alternative analysis, the value -2\beta_s = -0.12 +0.14 -0.16 rad is
found. In both measurements, the uncertainties due to U-spin breaking effects
up to 50% are included.Comment: updated to v2 with minor changes after journal revie
Measurement of the CP-violating phase in decays and limits on penguin effects
Time-dependent CP violation is measured in the channel for each resonant final state using data
collected with an integrated luminosity of 3.0 fb in collisions
using the LHCb detector. The final state with the largest rate,
, is used to measure the CP-violating angle to be . This result can be used to
limit the size of penguin amplitude contributions to CP violation measurements
in, for example, decays. Assuming approximate
SU(3) flavour symmetry and neglecting higher order diagrams, the shift in the
CP-violating phase is limited to be within the interval
[, +] at 95% confidence level. Changes to the limit
due to SU(3) symmetry breaking effects are also discussed.Comment: 18 pages, 6 figures; v2-updated from reviewers comments and added a
figur
Open data from the third observing run of LIGO, Virgo, KAGRA, and GEO
The global network of gravitational-wave observatories now includes five detectors, namely LIGO Hanford, LIGO Livingston, Virgo, KAGRA, and GEO 600. These detectors collected data during their third observing run, O3, composed of three phases: O3a starting in 2019 April and lasting six months, O3b starting in 2019 November and lasting five months, and O3GK starting in 2020 April and lasting two weeks. In this paper we describe these data and various other science products that can be freely accessed through the Gravitational Wave Open Science Center at https://gwosc.org. The main data set, consisting of the gravitational-wave strain time series that contains the astrophysical signals, is released together with supporting data useful for their analysis and documentation, tutorials, as well as analysis software packages
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