37 research outputs found
Implications of factorization for the determination of hadronic form factors in D_s^+ \ra \phi transition
Using factorization we determine the allowed domains of the ratios of form
factors, and , from the experimentally
measured ratio R_h \equiv \Gamma(D_s^+ \ra \phi \rho^+)/\Gamma(D_s^+ \ra \phi
\pi^+) assuming three different scenarios for the -dependence of the form
factors. We find that the allowed domains overlap with those obtained by using
the experimentally measured ratio R_{s\ell} = \Gamma(D^+_s \ra \phi \ell^+
\nu_{\ell})/\Gamma(D^+_s \ra \phi \pi^+) provided that the phenomenological
parameter is . Such a comparison presents a genuine test of
factorization. We calculate the longitudinal polarization fraction,
\Gamma_L/\Gamma \equiv \Gamma(D_s^+ \ra \phi_L \rho^+_L)/\Gamma(D_s^+ \ra \phi
\rho^+), in the three scenarios for the -dependence of the form factors
and emphasize the importance of measuring . Finally we
discuss the -distribution of the semileptonic decay and find that it is
rather insensitive to the scenarios for the -dependence of the form
factors, and unless very accurate data can be obtained it is unlikely to
discriminate between the different scenarios. Useful information on the value
of might be obtained by the magnitude of the -distribution near . However the most precise information on and would come from the
knowledge of the longitudinal and left-right transverse polarizations of the
final vector mesons in hadronic and/or semileptonic decays.Comment: Latex 10 pages( 4 figures), PAR/LPTHE/94-3
On the Determination of and from Hadronic Two Body Decays
{}From Class I decays : B^o \ra \pi^+ ( \rho^+ ) + D^- ( {D^*}^- ), we
determine , and from Class III decays : B^+ \ra \pi^+ ( \rho^+ ) +
\ol{D}^o ( {\ol{D}^*}^o ), we determine an allowed domain in the plane. We find that within one standard deviation errors, the allowed band
of from Class I decays is at least three standard deviations removed from
the allowed domain from Class III decays.If we expand the
experimental errors to two standard deviations we do find a small intersection
between the band and the allowed domain. The results
usually quoted in the literature lie in this intersection. We suggest : (1) an
independent measurement of the branching ratio for the Class III decay, B^+
\ra \rho^+ \ol{D}^o , (2) a high-statistics measurement of the branching ratio
of the Class I decay, B \ra \ol{D} ( \ol{D}^* ) + D_s ( D_s^* ) in both
charged states, and (3) a measurement of the longitudinal polarization fraction
in the Class III decay B^+ \ra \rho^+ {\ol{D}^*}^o to shed more light on the
questions involved .Comment: 9pages(Latex)+4 figures(PS file appended), PAR/LPTHE/94-2
Superheavy Majorana neutrino effects in the lepton-number violating e- + e- -> mu- + mu- process
In the minimal extension of the standard electroweak theory with ultra
massive Majorana neutrinos, the process e- + e- -> mu- + mu- could be
observable, in sharp contrast with the reaction e- + e- -> W- + W- which is
entirely controlled by neutrinoless double beta decay
data. Our result provides the process background that must be confronted "new
physics" models which postulate doubly charged particles, such as the gauge
bilepton Y^{-} in the model,
the left-right one,
and its supersymmetric version with doubly charged Higgs multiplets.Comment: 5 pages LaTeX + 1 postscript figure. Some references added; some new
paragraphs added in the tex
Nonfactorization and the decays and
In six chosen scenarios for the dependence of the form factors involved
in transition, we have determined the allowed domain
of and from the experimentally measured
ratios and in a scheme that uses the value of the phenomenological parameter and includes nonfactorized
contribution. We find that the experimentally measured values of and
from semileptonic decays of favor solutions which have significant
nonfactorized contribution, and, in particular, favors solutions in
scenarios where is either flat or decreasing with .Comment: 15 pages, Latex, four figure (available on request)
Hadronic Charmed Meson Decays Involving Axial Vector Mesons
Cabibbo-allowed charmed meson decays into a pseudoscalar meson and an
axial-vector meson are studied. The charm to axial-vector meson transition form
factors are evaluated in the Isgur-Scora-Grinstein-Wise quark model. The dipole
momentum dependence of the transition form factor and the presence of
a sizable long-distance -exchange are the two key ingredients for
understanding the data of . The mixing angle of
the strange axial-vector mesons is found to be or
from decays. The study of decays excludes the positive mixing-angle
solutions. It is pointed out that an observation of the decay at the level of will rule out
and favor the solution .
Though the decays are color suppressed, they are
comparable to and even larger than the color-allowed counterparts: and . The finite width effect of the axial-vector resonance is
examined. It becomes important for in particular when its width is
near 600 MeV.Comment: 19 page
Trans-ancestry genome-wide association study identifies 12 genetic loci influencing blood pressure and implicates a role for DNA methylation
We carried out a trans-ancestry genome-wide association and replication study of blood pressure phenotypes among up to 320,251 individuals of East Asian, European and South Asian ancestry. We find genetic variants at 12 new loci to be associated with blood pressure (P = 3.9 × 10-11 to 5.0 × 10-21). The sentinel blood pressure SNPs are enriched for association with DNA methylation at multiple nearby CpG sites, suggesting that, at some of the loci identified, DNA methylation may lie on the regulatory pathway linking sequence variation to blood pressure. The sentinel SNPs at the 12 new loci point to genes involved in vascular smooth muscle (IGFBP3, KCNK3, PDE3A and PRDM6) and renal (ARHGAP24, OSR1, SLC22A7 and TBX2) function. The new and known genetic variants predict increased left ventricular mass, circulating levels of NT-proBNP, and cardiovascular and all-cause mortality (P = 0.04 to 8.6 × 10-6). Our results provide new evidence for the role of DNA methylation in blood pressure regulation
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Extensive sequencing of seven human genomes to characterize benchmark reference materials
The Genome in a Bottle Consortium, hosted by the National Institute of Standards and Technology (NIST) is creating reference materials and data for human genome sequencing, as well as methods for genome comparison and benchmarking. Here, we describe a large, diverse set of sequencing data for seven human genomes; five are current or candidate NIST Reference Materials. The pilot genome, NA12878, has been released as NIST RM 8398. We also describe data from two Personal Genome Project trios, one of Ashkenazim Jewish ancestry and one of Chinese ancestry. The data come from 12 technologies: BioNano Genomics, Complete Genomics paired-end and LFR, Ion Proton exome, Oxford Nanopore, Pacific Biosciences, SOLiD, 10X Genomics GemCode WGS, and Illumina exome and WGS paired-end, mate-pair, and synthetic long reads. Cell lines, DNA, and data from these individuals are publicly available. Therefore, we expect these data to be useful for revealing novel information about the human genome and improving sequencing technologies, SNP, indel, and structural variant calling, and de novo assembly