3,536 research outputs found
New Particles from Belle
I report recent results on hidden charm spectroscopy from Belle. These
include: observation of a near-threshold enhancement in the omega-J/psi
invariant mass distribution for exclusive B-->K omega J/psi decays; evidence
for the decay X(3872)-->pi+pi-pi0 J/psi, where the pi+pi-pi0 invariant mass
distribution has a strong peak between 750 MeV and the kinematic limit of 775
MeV, suggesting that the process is dominated by the sub-threshold decay
X-->omega J/psi; and the observation of a peak near 3940 MeV in the J/psi
recoil mass spectrum for the inclusive continuum process e+e- --> J/psi X. The
results are based on a study of a 287 fb-1 sample of e+e- annihilation data
collected at center- of-mass energies around the Upsilon(4S) in the Belle
detector at the KEKB collider.Comment: 10 pages 12 figures. Invited talk at the 1st meeting of the APS
Topical Group on Hadronic Physics, Fermilab, October 24-26, 2004; revised to
correct some reference
The circadian clock: a tale of genetic–electrical interplay and synaptic integration
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record. Pioneering work in Drosophila uncovered the building blocks of
the molecular clock, consisting of transcription–translation
feedback loops (TTFLs). Subsequent experimental work
demonstrated that the mammalian TTFL is localized in cells and
tissues throughout the brain and body. Further research
established that neuronal activity forms an essential aspect of
clock function. However, how the membrane electrical activity
of clock neurons of the suprachiasmatic nucleus collaborate
with the TTFL to drive circadian behaviors remains mostly
unknown. Intercellular communication synchronizes the
individual circadian oscillators to produce a precise and
coherent circadian output. Here, we briefly review significant
research that is increasing our understanding of the critical
interactions between the TTFL and neuronal and glial activity in
the generation of circadian timing signals.Royal Society (Government)National Institute of Neurological Disorders and Stroke of the National Institutes of Healt
A Uniform Description of the States Recently Observed at B-factories
The newly found states Y(4260), Y(4361), Y(4664) and Z(4430) stir broad
interest in the study of spectroscopy in a typical charmonium scale. The
Y(4260) which was observed earlier has been interpreted as hybrid, molecular
state, and baryonium, etc. In this note we show for the first time that these
new structures, which are hard to be interpreted as charmonium states, can be
systematically embedded into an extended baryonium picture. According to this
assignment, the so far known characters of these states are understandable.
And, in the same framework, we make some predictions for experimenters to
measure in the future.Comment: 6 pages in Latex. to appear in J.Phys.
Supersymmetric Contributions to Bs->K+K-
Inspired by the existing calculation of B->piK decays in supersymmetry
(SUSY), we evaluate the dominant SUSY contributions to Bs->K+K-. We show that
the observables of this process can be significantly modified in the presence
of SUSY. In particular, the branching ratio can be increased considerably
compared to the prediction of the standard model (SM). The effect is even more
dramatic for the CP-violating asymmetries A_dir and A_mix. These asymmetries,
expected to be small in the SM (A_dir is predicted to take only positive
values), change drastically with SUSY contributions. The measurement of these
observables can therefore be used to detect the presence of physics beyond the
SM, and put constraints on its parameters.Comment: 17 pages, 2 figures. This new version contains one added reference
and some minor style change
Precision Flavour Physics with and
We show that a combined analysis of and
allows for new physics tests practically free of form factor uncertainties.
Residual theory errors are at the level of several percent. Our study
underlines the excellent motivation for measuring these modes at a Super
Flavour Factory.Comment: 26 pages, 2 figure
Dynamical mass of the O-type supergiant in Zeta Orionis A
A close companion of Zeta Orionis A was found in 2000 with the Navy Precision
Optical Interferometer (NPOI), and shown to be a physical companion. Because
the primary is a supergiant of type O, for which dynamical mass measurements
are very rare, the companion was observed with NPOI over the full 7-year orbit.
Our aim was to determine the dynamical mass of a supergiant that, due to the
physical separation of more than 10 AU between the components, cannot have
undergone mass exchange with the companion. The interferometric observations
allow measuring the relative positions of the binary components and their
relative brightness. The data collected over the full orbital period allows all
seven orbital elements to be determined. In addition to the interferometric
observations, we analyzed archival spectra obtained at the Calar Alto, Haute
Provence, Cerro Armazones, and La Silla observatories, as well as new spectra
obtained at the VLT on Cerro Paranal. In the high-resolution spectra we
identified a few lines that can be associated exclusively to one or the other
component for the measurement of the radial velocities of both. The combination
of astrometry and spectroscopy then yields the stellar masses and the distance
to the binary star. The resulting masses for components Aa of 14.0 solar masses
and Ab of 7.4 solar masses are low compared to theoretical expectations, with a
distance of 294 pc which is smaller than a photometric distance estimate of 387
pc based on the spectral type B0III of the B component. If the latter (because
it is also consistent with the distance to the Orion OB1 association) is
adopted, the mass of the secondary component Ab of 14 solar masses would agree
with classifying a star of type B0.5IV. It is fainter than the primary by about
2.2 magnitudes in the visual. The primary mass is then determined to be 33
solar masses
EM Decay of X(3872) as the charmonium
The recently BaBar results raise the possibility that X(3872) has negative
parity. This makes people reconsider assigning X(3872) to the state. In this paper we give a general form of the wave function of
mesons. By solving the instantaneous Bethe-Salpeter equation, we get
the mass spectrum and corresponding wave functions. We calculate
electromagnetic decay widths of the first state which we assume to be
the X(3872) particle. The results are keV, eV and keV. The ratio of branch fractions
of the second and first channel is about 0.002, which is inconsistent with the
experimental value . So X(3872) is unlikely to be a
charmonium state. In addition, we obtain a relatively large decay width for
channel which is keV.Comment: Revised versio
Women in engineering: Promoting identity exploration and professional development
Engineering colleges are concerned about retention of women, especially women of color, in their programs. One possible solution is to promote undergraduate women\u27s engineering identity. This paper describes an evaluation of a one-day technical and professional development conference for undergraduate women in engineering and computer science, which focused on understanding and facilitating engineering identity. Data on the impact of the conference and engineering identity, were collected in pre- and post-conference surveys. The pre-conference survey assessed demographic information (e.g., first generation status, ethnicity), engineering student identity (i.e., commitment to engineering major; engineering competence, and engineering agency), social support, and reasons for attending. The post-conference survey assessed engineering student identity, ratings of self- and engineer creativity, professional identity, and evaluations of the conference. 193 participants returned pre-conference surveys and 103 returned post-conference surveys. Most were engineering (54%) and computer science (38%) majors; 46% were Asian, 28% LatinX; and 65% received financial aid. Correlations, MANOVA, regression, and content analyses were used to analyze the data. Participants reported the conference was highly valuable. Both pre- and post-conference surveys revealed positive associations between commitment, competence, and agency, suggesting that undergraduate women view their engineering identities as a coherent set. Results indicated that the strength of a participant\u27 professional identity is shaped by first-generation status and knowing an engineer. They also indicated that women undergraduates do not rate themselves as being as creative as a typical engineer, and there is a strong association between self-ratings of creativity and professional identity. Engineering identity is discussed in the context of participants\u27 reported goals for the conference and its benefits. Suggestions for promoting engineering identity are described
Quenched lattice calculation of semileptonic heavy-light meson form factors
We calculate, in the continuum limit of quenched lattice QCD, the matrix
elements of the heavy-heavy vector current between heavy-light pseudoscalar
meson states. We present the form factors for different values of the initial
and final meson masses at finite momentum transfer. In particular, we calculate
the non-perturbative correction to the differential decay rate of the process B
--> D l nu including the case of a non-vanishing lepton mass.Comment: 16 pages, 10 figures, version accepted for publication on JHE
The Relationship Between Ethical Decision Making and Ethical Reasoning in Information Technology Students
This study examined undergraduate information technology (IT) students\u27 (N=122) level of ethical reasoning and decision making at a Midwestern university. The purpose was to determine whether IT students\u27 level of ethical reasoning provided information about the degree of their ethical decision making. The Defining Issues Test-2 (DIT-2) was used as well as an Ethics in IT survey instrument containing 21 vignettes related to the field of information technology. The findings did reveal a correlation between ethical reasoning scores (as measured by the DIT-2) and the level of ethical decision making related to an IT setting (as measured by the Ethics in IT survey)
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