265 research outputs found
Model-Independent Semileptonic Form Factors Using Dispersion Relations
We present a method for parametrizing heavy meson semileptonic form factors
using dispersion relations, and from it produce a two-parameter description of
the B -> B elastic form factor. We use heavy quark symmetry to relate this
function to B -> D* l nu form factors, and extract
|V_cb|=0.0355^{+0.0029}_{-0.0025} from experimental data with a least squares
fit. Our method eliminates model-dependent uncertainties inherent in choosing a
parametrization for the extrapolation of the differential decay rate to
threshold.Comment: uses lanlmac(harvmac) and epsf, 12 pages, 1 eps figure included (Talk
by BG at the 6-th International Symposium on Heavy Flavour Physics, Pisa,
Italy, 6--10 June, 1995
QED Logarithms in the Electroweak Corrections to the Muon Anomalous Magnetic Moment
We employ an effective Lagrangian approach to derive the leading-logarithm
two-loop electroweak contributions to the muon anomalous magnetic moment, a_mu.
We show that these corrections can be obtained using known results on the
anomalous dimensions of composite operators. We confirm the result of Czarnecki
et al. for the bosonic part and present the complete sin^2 \theta_W dependence
of the fermionic contribution. The approach is then used to compute the
leading-logarithm three-loop electroweak contribution to a_mu. Finally we
derive, in a fairly model-independent way, the QED improvement of new-physics
contributions to a_mu and to the electric dipole moment (EDM) of the electron.
We find that the QED corrections reduce the effect of new physics at the
electroweak scale by 6% (for a_mu) and by 11% (for the electron EDM).Comment: 13 page
Form Factors
The bounds on the form factors for decay are
studied. Constrained by lattice data and a constrained conformal mapping, the
more informations can be obtained for form-factor which dominates
the decay rate at large . Specifically, we confirm a moderately increasing
behavior of this form factor.Comment: 15 pages, Latex, 4 figure
Analyticity, Shapes of Semileptonic Form Factors, and B to pi l nu
We give a pedagogical discussion of the physics underlying dispersion
relation-derived parameterizations of form factors describing B -> pi l nu and
B -> D l nu. Moments of the dispersion relations are shown to provide
substantially tighter constraints on the f_+ (t) form factor describing B -> pi
l nu than the unweighted dispersion relation alone. Heavy quark spin symmetry
relations between the B -> pi l nu and B^* -> pi l nu form factors enables such
constraints to be tightened even further.Comment: 18 pages, Latex, three eps figures include
The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment
The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in
operation since July 2014. This paper describes the second data release from
this phase, and the fourteenth from SDSS overall (making this, Data Release
Fourteen or DR14). This release makes public data taken by SDSS-IV in its first
two years of operation (July 2014-2016). Like all previous SDSS releases, DR14
is cumulative, including the most recent reductions and calibrations of all
data taken by SDSS since the first phase began operations in 2000. New in DR14
is the first public release of data from the extended Baryon Oscillation
Spectroscopic Survey (eBOSS); the first data from the second phase of the
Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2),
including stellar parameter estimates from an innovative data driven machine
learning algorithm known as "The Cannon"; and almost twice as many data cubes
from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous
release (N = 2812 in total). This paper describes the location and format of
the publicly available data from SDSS-IV surveys. We provide references to the
important technical papers describing how these data have been taken (both
targeting and observation details) and processed for scientific use. The SDSS
website (www.sdss.org) has been updated for this release, and provides links to
data downloads, as well as tutorials and examples of data use. SDSS-IV is
planning to continue to collect astronomical data until 2020, and will be
followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14
happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov
2017 (this is the "post-print" and "post-proofs" version; minor corrections
only from v1, and most of errors found in proofs corrected
Present Status of Inclusive Rare B Decays
We give a status report on inclusive rare B decays, highlighting recent
developments and open problems. We focus on the decay modes , and and on their
role in the search for new physics. Most of the inclusive rare B decays are
important modes of flavour physics due to the small hadronic uncertainties.
They can be regarded as laboratories to search for new physics. We collect the
experimental data already available from CLEO and the factories BABAR and
BELLE. We review the NLL and NNLL QCD calculations of the inclusive decay rates
that were recently completed, and discuss future prospects, especially the
issue of the charm mass scheme ambiguity. Finally, we analyse the
phenomenological impact of these decay modes, in particular on the CKM
phenomenology and on the indirect search for supersymmetry. We also briefly
discuss direct CP violation in inclusive rare B decays, as well as the rare
kaon decays and , which
offer complementary theoretically clean information.Comment: 80 pages, 37 figures, latex, references added Invited contribution to
Reviews of Modern Physic
Nuclear energy in the public sphere: Anti-nuclear movements vs. industrial lobbies in Spain (1962-1979)
The final publication is available at Springer via http://dx.doi.org/10.1007/s11024-014-9263-0This article examines the role of the Spanish Atomic Forum as the
representative of the nuclear sector in the public arena during the golden years of the
nuclear power industry from the 1960s to 1970s. It focuses on the public image
concerns of the Spanish nuclear lobby and the subsequent information campaigns
launched during the late 1970s to counteract demonstrations by the growing and
heterogeneous anti-nuclear movement. The role of advocacy of nuclear energy by
the Atomic Forum was similar to that in other countries, but the situation in Spain
had some distinguishing features. Anti-nuclear protest in Spain peaked in 1978
paralleling the debates of a new National Energy Plan in Congress, whose first draft
had envisaged a massive nuclearization of the country. We show how the approval
of the Plan in July 1979, with a significant reduction in the nuclear energy component,
was influenced by the anti-nuclear protest movements in Spain. Despite the
efforts of the Spanish Atomic Forum to counter its message, the anti-nuclear
movement was strengthened by reactions to the Three Mile Island accident in March
1979
Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe
We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median ). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July
QCD and strongly coupled gauge theories : challenges and perspectives
We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.Peer reviewe
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