584 research outputs found
Extracting and using photon polarization information in radiative B decays
We discuss the uses of conversion electron pairs for extracting photon
polarization information in weak radiative B decays. Both cases of leptons
produced through a virtual and real photon are considered. Measurements of the
angular correlation between the and decay planes in decays can be used to determine the
helicity amplitudes in the radiative decay. A large
right-handed helicity amplitude in decays is a signal of new physics.
The time-dependent CP asymmetry in the decay angular correlation is shown
to measure and with little hadronic uncertainty.Comment: 15 pages ReVTeX with 1 included figure; 2 references adde
Testing the dynamics of B -> \pi\pi and constraints on \alpha
In charmless nonleptonic B decays to \pi\pi or \rho\rho, the "color allowed"
and "color suppressed" tree amplitudes can be studied in a systematic expansion
in \alphas(mb) and \Lambda/mb. At leading order in this expansion their
relative strong phase vanishes. The implications of this prediction are
obscured by penguin contributions. We propose to use this prediction to test
the relative importance of the various penguin amplitudes using experimental
data. The present B->\pi\pi data suggest that there are large corrections to
the heavy quark limit, which can be due to power corrections to the tree
amplitudes, large up-quark penguin amplitude, or enhanced weak annihilation.
Because the penguin contributions are smaller, the heavy quark limit is more
consistent with the B->\rho\rho data, and its implications may become important
for the extraction of \alpha from this mode in the future.Comment: 8 pages, 6 figures, includes special style file; final version to
appear in Phys. Rev.
Mental Health Care Consumption and Outcomes: Considering Preventative Strategies Across Race and Class
In previous work (Richman 2007), we found that even under conditions of equal insurance coverage and access to mental healthcare providers, whites and high-income individuals consume more outpatient mental health services than nonwhites and low-income individuals. We follow-up that study to determine (1) whether nonwhite and low-income individuals obtain medical substitutes to mental healthcare, and (2) whether disparate consumption leads to disparate health outcomes. We find that nonwhites and low-income individuals are more likely than their white and high-income counterparts to obtain mental health care from general practitioners over mental healthcare providers, and nearly twice as likely not to follow up with a mental health provider after hospitalization with a mental health diagnosis. We further are unable to find any evidence that this leads to adverse health outcomes. These findings echo concern expressed in Richman (2007) that low-income and nonwhite individuals might be paying for health services that primarily benefit their white and more affluent coworkers
Staccato: A Bug Finder for Dynamic Configuration Updates (Artifact)
This artifact is based on Staccato, a tool for finding errors in dynamic configuration update (DCU) implementations. Dynamic configuration update refers to configuration changes that occur at runtime without program restart. Errors in DCU implementations occur when stale data - computed from old configurations - or inconsistent data - computed from different configurations - are used. Staccato uses a dynamic analysis in the style of taint analysis to detect these errors. Staccato supports concurrent programs running on commodity JVMs. We evaluated Staccato on three open-source applications and found errors in all of them
Taming the Static Analysis Beast
While industrial-strength static analysis over large, real-world codebases has become commonplace, so too have difficult-to-analyze language constructs, large libraries, and popular frameworks. These features make constructing and evaluating a novel, sound analysis painful, error-prone, and tedious. We motivate the need for research to address these issues by highlighting some of the many challenges faced by static analysis developers in today\u27s software ecosystem. We then propose our short- and long-term research agenda to make static analysis over modern software less burdensome
The photon polarization in B -> X gamma in the standard model
The standard model prediction for the decay amplitude
with a right-handed photon is believed to be tiny, suppressed by ,
compared to the amplitude with a left-handed photon. We show that this
suppression is fictitious: in inclusive decays, the ratio of these two
amplitudes is only suppressed by , and in exclusive decays by
. The suppression is not stronger in decays
than it is in . We estimate that the time dependent CP
asymmetries in , , , and
are of order 0.1 and that they have significant
uncertainties.Comment: Clarifications in the exclusive section, references adde
Germanium:gallium photoconductors for far infrared heterodyne detection
Highly compensated Ge:Ga photoconductors have been fabricated and evaluated for high bandwidth heterodyne detection. Bandwidths up to 60 MHz have been obtained with corresponding current responsivity of 0.01 A/W
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