2,784 research outputs found
Semileptonic B to D decays at nonzero recoil with 2+1 flavors of improved staggered quarks. An update
The Fermilab Lattice and MILC collaborations are completing a comprehensive
program of heavy-light physics on MILC (2+1)-flavor asqtad ensembles with
lattice spacings as small as 0.045 fm and light-to-strange-quark mass ratios as
low as 1/20. We use the Fermilab interpretation of the clover action for heavy
valence quarks and the asqtad action for the light valence quarks. The central
goal of the program is to provide ever more exacting tests of the unitarity of
the CKM matrix. We present preliminary results for one part of the program,
namely the analysis of the semileptonic decay B -> D l nu at nonzero recoil.Comment: 7 pp, 7 figs, Lattice 201
Detuning effects in the one-photon mazer
The quantum theory of the mazer in the non-resonant case (a detuning between
the cavity mode and the atomic transition frequencies is present) is written.
The generalization from the resonant case is far from being direct. Interesting
effects of the mazer physics are pointed out. In particular, it is shown that
the cavity may slow down or speed up the atoms according to the sign of the
detuning and that the induced emission process may be completely blocked by use
of a positive detuning. It is also shown that the detuning adds a potential
step effect not present at resonance and that the use of positive detunings
defines a well-controlled cooling mechanism. In the special case of a mesa
cavity mode function, generalized expressions for the reflection and
transmission coefficients have been obtained. The general properties of the
induced emission probability are finally discussed in the hot, intermediate and
cold atom regimes. Comparison with the resonant case is given.Comment: 9 pages, 8 figure
Non-Abelian anyonic interferometry with a multi-photon spin lattice simulator
Recently a pair of experiments demonstrated a simulation of Abelian anyons in
a spin network of single photons. The experiments were based on an Abelian
discrete gauge theory spin lattice model of Kitaev. Here we describe how to use
linear optics and single photons to simulate non-Abelian anyons. The scheme
makes use of joint qutrit-qubit encoding of the spins and the resources
required are three pairs of parametric down converted photons and 14 beam
splitters.Comment: 13 pages, 5 figures. Several references added in v
糖尿病培训手册在培养糖尿病护士的应用
Objective: To explore the nursing service mode for specialized nurses in diabetes and its application effect. Methods:In view of the actual situation of our hospital, a special training manual named with Diabetes training manual was prior composed. 40 specialized nurses in diabetes were trained with the special training manual. Training lasted for 3 months. After the training, the specialized nurses were assessed with the specialty knowledge of Diabetes Mellitus, the skill of clinical procedures, and the knowledge about patients' health education. Results: The skill of the trained nurses was improved. The satisfaction of patients was enhanced.Conclusion: Diabetes training manual can be used for specialized nurses in diabetes.目的 探讨糖尿病护士培训方式。方法 对2013年1—10月本院内分泌科的40名糖尿病护士培训,根据以往医院的培训,结合本院实际,应用自编的糖尿病培训手册,最后考核糖尿病专科理论、操作及宣教能力考核,培训时间为3个月。结果 培训前与培训后比较差别有统计学意义(P<0.05),理论、操作及健康宣教能力较培训前提高;提高了患者及新护士的满意度。结论 糖尿病培训手册可以用于培养糖尿病新护士
B_s->D_s/B->D Semileptonic Form-Factor Ratios and Their Application to BR(B^0_s->\mu^+\mu^-)
We calculate form-factor ratios between the semileptonic decays
\bar{B}->D^+\ell^-\bar{\nu} and \bar{B}_s->D_s^+\ell^-\bar{\nu} with lattice
QCD. These ratios are a key theoretical input in a new strategy to determine
the fragmentation fractions of the neutral B decays, which are needed for
measurements of BR(B^0_s-> \mu^+\mu^-). We use the MILC ensembles of gauge
configurations with 2+1 flavors of sea quarks at two lattice spacings of
approximately 0.12 fm and 0.09 fm. We use the model-independent
z-parametrization to extrapolate our simulation results at small recoil toward
maximum recoil. Our results for the form-factor ratios are
and
. In
contrast to a QCD sum-rule calculation, no significant departure from U-spin
(ds) symmetry is observed.Comment: 30 pages, 11 figures. Fig. 1 updated. Table II added. Conforms with
version published in Physical Review D, except typos fixed, as in the PRD
Erratum, in Table V (previously Table IV in arXiv v1). Results unchange
Update of from the form factor at zero recoil with three-flavor lattice QCD
We compute the zero-recoil form factor for the semileptonic decay
(and modes related by isospin and charge
conjugation) using lattice QCD with three flavors of sea quarks. We use an
improved staggered action for the light valence and sea quarks (the MILC
\asqtad\ configurations), and the Fermilab action for the heavy quarks. Our
calculations incorporate higher statistics, finer lattice spacings, and lighter
quark masses than our 2008 work. As a byproduct of tuning the new data set, we
obtain the and hyperfine splittings with few-MeV accuracy. For the
zero-recoil form factor, we obtain , where the
first error is statistical and the second is the sum in quadrature of all
systematic errors. With the latest HFAG average of experimental results and a
cautious treatment of QED effects, we find . The
QCD error is now commensurate with the experimental error.Comment: 53 pages, 12 figures; expanded discussion of correlator fits, typos
corrected, conforms to version published in PR
Semileptonic B to D decays at nonzero recoil with 2+1 flavors of improved staggered quarks
The Fermilab Lattice-MILC collaboration is completing a comprehensive program
of heavy-light physics on the MILC (2+1)-flavor asqtad ensembles with lattice
spacings as small as 0.045 fm and light-to-strange-quark mass ratios as low as
1/20. We use the Fermilab interpretation of the clover action for heavy valence
quarks and the asqtad action for light valence quarks. The central goal of the
program is to provide ever more exacting tests of the unitarity of the CKM
matrix. We give a progress report on one part of the program, namely the
analysis of the semileptonic decay B to D at both zero and nonzero recoil.
Although final results are not presented, we discuss improvements in the
analysis methods, the statistical errors, and the parameter coverage that we
expect will lead to a significant reduction in the final error for |V_cb| from
this decay channel.Comment: 7 pages, 3 figures, LATTICE 2011 conferenc
form factors for new-physics searches from lattice QCD
The rare decay arises from flavor-changing
neutral currents and could be sensitive to physics beyond the Standard Model.
Here, we present the first - QCD calculation of the
tensor form factor . Together with the vector and scalar form factors
and from our companion work [J. A. Bailey , Phys. Rev. D
92, 014024 (2015)], these parameterize the hadronic contribution to
semileptonic decays in any extension of the Standard Model. We obtain the total
branching ratio in
the Standard Model, which is the most precise theoretical determination to
date, and agrees with the recent measurement from the LHCb experiment [R. Aaij
, JHEP 1212, 125 (2012)]. Note added: after this paper was submitted
for publication, LHCb announced a new measurement of the differential decay
rate for this process [T. Tekampe, talk at DPF 2015], which we now compare to
the shape and normalization of the Standard-Model prediction.Comment: V3: Corrected errors in results for Standard-Model differential and
total decay rates in abstract, Fig. 3, Table IV, and outlook. Added new
preliminary LHCb data to Fig. 3 and brief discussion after outlook. Replaced
outdated correlation matrix in Table III with correct final version. Other
minor wording changes and references added. 7 pages, 4 tables, 3 figure
decay form factors from three-flavor lattice QCD
We compute the form factors for the semileptonic decay
process in lattice QCD using gauge-field ensembles with 2+1 flavors of sea
quark, generated by the MILC Collaboration. The ensembles span lattice spacings
from 0.12 to 0.045 fm and have multiple sea-quark masses to help control the
chiral extrapolation. The asqtad improved staggered action is used for the
light valence and sea quarks, and the clover action with the Fermilab
interpretation is used for the heavy quark. We present results for the form
factors , , and , where is the momentum
transfer, together with a comprehensive examination of systematic errors.
Lattice QCD determines the form factors for a limited range of , and we
use the model-independent expansion to cover the whole kinematically
allowed range. We present our final form-factor results as coefficients of the
expansion and the correlations between them, where the errors on the
coefficients include statistical and all systematic uncertainties. We use this
complete description of the form factors to test QCD predictions of the form
factors at high and low . We also compare a Standard-Model calculation of
the branching ratio for with experimental data.Comment: V2: Fig.7 added. Typos text corrected. Reference added. Version
published in Phys. Rev.
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