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 $(K\pi)$ and $(e^+e^-)$ decay planes in $B\to K^*(\to K\pi)\gamma^{(*)}(\to e^+e^-)$ decays can be used to determine the helicity amplitudes in the radiative $B\to K^*\gamma$ decay. A large right-handed helicity amplitude in $\bar B$ decays is a signal of new physics. The time-dependent CP asymmetry in the $B^0$ decay angular correlation is shown to measure $\sin 2\beta$ and $\cos 2\beta$ 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 $B\to X_{s,d}\gamma$ decay amplitude with a right-handed photon is believed to be tiny, suppressed by $m_{s,d}/m_b$, 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 $g_s/(4\pi)$, and in exclusive decays by $\Lambda_{QCD}/m_b$. The suppression is not stronger in $B\to X_d\gamma$ decays than it is in $B\to X_s\gamma$. We estimate that the time dependent CP asymmetries in $B\to K^*\gamma$, $\rho\gamma$, $K_S\pi^0\gamma$, and $\pi^+\pi^-\gamma$ 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