56,255 research outputs found

### Determinations of |V_ub| and |V_cb| from measurements of B -> X_u,c\ell\nu differential decay rates

Methods are described in the framework of light-cone expansion which allow
one to determine the Cabibbo-Kobayashi-Maskawa matrix elements |V_ub| and
|V_cb| from measurements of the differential decay rates as a function of the
scaling variables in the inclusive semileptonic decays of B mesons. By these
model-independent methods the dominant hadronic uncertainties can be avoided
and the B -> X_u\ell\nu decay can be very efficiently differentiated from the B
-> X_c\ell\nu decay, which may lead to precise determinations of |V_ub| and
|V_cb|.Comment: 11 pages, 2 figures, version as published in Mod. Phys. Lett. A, more
discussion, references added, title chang

### Dynamics underlying Box-office: Movie Competition on Recommender Systems

We introduce a simple model to study movie competition in the recommender
systems. Movies of heterogeneous quality compete against each other through
viewers' reviews and generate interesting dynamics of box-office. By assuming
mean-field interactions between the competing movies, we show that run-away
effect of popularity spreading is triggered by defeating the average review
score, leading to hits in box-office. The average review score thus
characterizes the critical movie quality necessary for transition from
box-office bombs to blockbusters. The major factors affecting the critical
review score are examined. By iterating the mean-field dynamical equations, we
obtain qualitative agreements with simulations and real systems in the
dynamical forms of box-office, revealing the significant role of competition in
understanding box-office dynamics.Comment: 8 pages, 6 figure

### Make and learn: A CS Principles course based on the Arduino platform

We present preliminary experiences in designing a Computer Science Principles undergraduate course for all majors that is based on physical computing with the Arduino microprocessor platform. The course goal is to introduce students to fundamental computing concepts in the context of developing concrete products. This physical computing approach is different from other existing CS Principles courses. Students use the Arduino platform to design tangible interactive systems that are personally and socially relevant to them, while learning computing concepts and reflecting on their experiences. In a previous publication [1], we reported on assessment results of using the Arduino platform in an Introduction to Digital Design course. We have introduced this platform in an introductory computing course at the University of Hartford in the past year as well as in a Systems Fundamentals Discovery Course at the University of New Hampshire to satisfy the general education requirements in the Environment, Technology, and Society category. Our goal is to align the current curriculum with the CS Principles framework to design a course that engages a broader audience through a creative making and contextualized learning experience

### Analysis of hadronic invariant mass spectrum in inclusive charmless semileptonic B decays

We make an analysis of the hadronic invariant mass spectrum in inclusive
charmless semileptonic B meson decays in a QCD-based approach. The decay width
is studied as a function of the invariant mass cut. We examine their
sensitivities to the parameters of the theory. The theoretical uncertainties in
the determination of $|V_{ub}|$ from the hadronic invariant mass spectrum are
investigated. A strategy for improving the theoretical accuracy in the value of
$|V_{ub}|$ is described.Comment: 13 pages, 5 Postscript figure

### Semi-Inclusive B\to K(K^*) X Decays with Initial Bound State Effects

The effects of initial $b$ quark bound state for the semi-inclusive decays
$B\to K(K^*) X$ are studied using light cone expansion and heavy quark
effective theory methods. We find that the initial bound state effects on the
branching ratios and CP asymmetries are small. In the light cone expansion
approach, the CP-averaged branching ratios are increased by about 2% with
respect to the free $b$-quark decay. For $\bar B^0 \to K^- (K^{*-}) X$, the
CP-averaged branching ratios are sensitive to the phase $\gamma$ and the CP
asymmetry can be as large as 7% (14%), whereas for $B^-\to \bar K^0 (\bar
K^{*0})X$ the CP-averaged branching ratios are not sensitive to $\gamma$ and
the CP asymmetries are small ($< 1%$). The CP-averaged branching ratios are
predicted to be in the ranges $(0.53 \sim 1.5)\times 10^{-4}$ [$(0.25 \sim
2.0)\times 10^{-4}$] for $\bar B^0 \to K^- (K^{*-})X$ and $(0.77 \sim
0.84)\times 10^{-4}$ [$(0.67 \sim 0.74)\times 10^{-4}$] for $B^-\to \bar K^0
(\bar K^{*0}) X$, depending on the value of the CP violating phase $\gamma$. In
the heavy quark effective theory approach, we find that the branching ratios
are decreased by about 10% and the CP asymmetries are not affected. These
predictions can be tested in the near future.Comment: 29 pages, 12 ps figure

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