57 research outputs found
Measuring sin 2\beta in Bs(t) -> phi K_s
We show that, unlike other pure b -> d penguin processes, the decay Bs(t) ->
phi K_s is dominated by a single amplitude, that of the internal t-quark. The
contributions of the u- and c-quark operators each vanish due to a cancellation
between the (V-A) \otimes (V-A) and (V-A) \otimes (V+A) matrix elements. Thus,
the indirect CP asymmetry in this decay probes sin 2\beta. Although this
cancellation is complete only for certain values of the s- and b-quark masses,
the theoretical uncertainty on sin 2\beta is still less than 10% over most
(~80%) of the parameter space. By measuring the direct CP asymmetry, one can
get a better idea of the probable error on sin 2\beta.Comment: 15 pages, LaTeX, 4 figure
Considerations for maintaining family diversity in commercially mass-spawned penaeid shrimp: a case study on Penaeus monodon
Skewed family distributions are common in aquaculture species that are highly fecund, communally (mass) spawned, and/or communally reared. The magnitude of skews pose challenges for maintaining family-specific genetic diversity, as increased resources are required to detect individuals from underrepresented families, or reliably determine relative survival as a measure of family performance. There is limited understanding of family skews or changes in family proportion of communally reared shrimp under commercial rearing conditions and particularly how this may affect genotyping strategies to recover family performance data in breeding programs. In this study, three separate batches of shrimp, Penaeus monodon, were communally spawned and reared, and then sampled as larvae when ponds were stocked at 30 days of culture (DOC) and as juveniles from commercial ponds during harvest at 150 DOC. A total of 199 broodstock contributed to the 5,734 progeny that were genotyped with a custom multiplex single nucleotide polymorphism (SNP) panel, and family assignments were cross-referenced using two parentage assignment methods, CERVUS and COLONY. A total of 121 families were detected, with some families contributing up to 11% of progeny at 30 DOC and up to 18% of progeny at harvest. Significant changes were detected for 20% of families from 30 to 150 DOC, with up to a 9% change in relative contribution. Family skew data was applied in several models to determine the optimal sample size to detect families, along with the ability to detect changes in relative family contribution over time. Results showed that an order of magnitude increase in sampling was required to capture the lowest represented 25% of families, as well as significantly improve the accuracy to determine changes in family proportion from 30 to 150 DOC. Practical measures may be implemented at the hatchery to reduce family skews; a cost-effective measure may be to address the initial magnitude differences in viable progeny produced among families, by pooling equal quantities of hatched larvae from each family. This study demonstrates the relationships between skews in families under commercial conditions, the ability to accurately detect families, and the balance of sampling effort and genotyping cost in highly fecund species such as shrimp
Two body decays of the -quark: Applications to direct CP violation, searches for electro-weak penguins and new physics
A systematic experimental search for two-body hadronic decays of the b-quark
of the type b to quark + meson is proposed. These reactions have a well defined
experimental signature and they should be theoretically cleaner compared to
exclusive decays. Many modes have appreciable branching ratios and partial rate
asymmetries may also be quite large (about 8-50%) in several of them. In a few
cases electroweak penguins appear to be dominant and may be measurable. CP
violating triple correlation asymmetries provide a clean test of the Standard
Model.Comment: 12 pages 1 figure 1 tabl
Financial incentives to promote active travel: an evidence review and economic framework
ContextFinancial incentives, including taxes and subsidies, can be used to encourage behavior change. They are common in transport policy for tackling externalities associated with use of motor vehicles, and in public health for influencing alcohol consumption and smoking behaviors. Financial incentives also offer policymakers a compromise between “nudging,” which may be insufficient for changing habitual behavior, and regulations that restrict individual choice.Evidence acquisitionThe literature review identified studies published between January 1997 and January 2012 of financial incentives relating to any mode of travel in which the impact on active travel, physical activity, or obesity levels was reported. It encompassed macroenvironmental schemes, such as gasoline taxes, and microenvironmental schemes, such as employer-subsidized bicycles. Five relevant reviews and 20 primary studies (of which nine were not included in the reviews) were identified.Evidence synthesisThe results show that more-robust evidence is required if policymakers are to maximize the health impact of fiscal policy relating to transport schemes of this kind.ConclusionsDrawing on a literature review and insights from the SLOTH (sleep, leisure, occupation, transportation, and home-based activities) time-budget model, this paper argues that financial incentives may have a larger role in promoting walking and cycling than is acknowledged generally
The Universal One-Loop Effective Action
We present the universal one-loop effective action for all operators of
dimension up to six obtained by integrating out massive, non-degenerate
multiplets. Our general expression may be applied to loops of heavy fermions or
bosons, and has been checked against partial results available in the
literature. The broad applicability of this approach simplifies one-loop
matching from an ultraviolet model to a lower-energy effective field theory
(EFT), a procedure which is now reduced to the evaluation of a combination of
matrices in our universal expression, without any loop integrals to evaluate.
We illustrate the relationship of our results to the Standard Model (SM) EFT,
using as an example the supersymmetric stop and sbottom squark Lagrangian and
extracting from our universal expression the Wilson coefficients of
dimension-six operators composed of SM fields.Comment: 30 pages, v2 contains additional comments and corrects typos, version
accepted for publication in JHE
CP Violation in Top Physics
CP violation in top physics is reviewed. The Standard Model has negligible
effects, consequently CP violation searches involving the top quark may
constitute the best way to look for physics beyond the Standard Model.
Non-standard sources of CP violation due to an extended Higgs sector with and
without natural flavor conservation and supersymmetric theories are discussed.
Experimental feasibility of detecting CP violation effects in top quark
production and decays in high energy e+ e-, gamma-gamma, mu+ mu-, pp and p-bar
p colliders are surveyed. Searches for the electric, electro-weak and the
chromo-electric dipole moments of the top quark in e+ e- -> t-bar t and in p p
-> t-bar t X are descibed. In addition, other mechanisms that appear promising
for experiments, e.g., tree-level CP violation in e+ e- -> t-bar t h, t-bar t
Z, t-bar t nu_e-bar nu_e and in the top decay t -> b tau nu_tau and CP
violation driven by s-channel Higgs exchanges in p p, gamma gamma, mu+ mu- ->
t-bar t etc., are also discussed.Comment: 253 pages, 70 figures, A 2-up version of this postscript file may be
obtained at http://thy.phy.bnl.gov/~soni/topreview.htm
The Possibility of Large Direct CP Violation in B to K pi-Like Modes Due to Long Distance Rescattering Effects and Implications for the Angle gamma
We consider the strong rescattering effects that can occur in the decays such
as B -> K pi, K* pi, K rho... and their impact on direct CP violation in these
modes. First we discuss, in general, how the CPT theorem constrains the
resulting pattern of partial rate asymmetries leading to different brands of
direct CP. Traditional discussions have centered around the absorptive part of
the penguin graph which has Delta I=0 in b -> s transitions and as a result
causes ``simple'' CP violation; long-distance final state rescattering effects,
in general, will lead to a different pattern of CP: ``compound'' CP violation.
Predictions of simple CP are quite distinct from that of compound CP. Final
states rescattering phases in B decays are unlikely to be small possibly
causing large compound CP violating partial rate asymmetries in these modes.
CPT theorem requires a cancellation of PRA due to compound CP amongst the
states themselves; thus there can be no net cancellation with other
states such as K*\pi, K\rho etc. Therefore, each class of such modes, namely K
pi, K rho, K^*pi, K a_1 etc. can have large direct CP emanating from
rescattering effects. Various repercussions for the angle are also
discussed.Comment: 45 pages; 5 figures. In replacement we have : 1) corrected many
typos, 2) added references, 3) decided to subdivide Simple CP into 2
categories and 4) Modified figure 3 to explain tha
B-factory Physics from Effective Supersymmetry
We discuss how to extract non-Standard Model effects from B-factory
phenomenology. We then analyze the prospects for uncovering evidence for
Effective Supersymmetry, a class of supersymmetric models which naturally
suppress flavor changing neutral currents and electric dipole moments without
squark universality or small CP violating phases, in experiments at BaBar,
BELLE, HERA-B, CDF/D0 and LHC-B.Comment: 5 pages, 2 figures, revtex, eps
Genetic variants regulating ORMDL3 expression contribute to the risk of childhood asthma
Asthma is caused by a combination of poorly understood genetic and environmental factors(1,2). We have systematically mapped the effects of single nucleotide polymorphisms ( SNPs) on the presence of childhood onset asthma by genome-wide association. We characterized more than 317,000 SNPs in DNA from 994 patients with childhood onset asthma and 1,243 non-asthmatics, using family and case-referent panels. Here we show multiple markers on chromosome 17q21 to be strongly and reproducibly associated with childhood onset asthma in family and case-referent panels with a combined P value of P < 10(-12). In independent replication studies the 17q21 locus showed strong association with diagnosis of childhood asthma in 2,320 subjects from a cohort of German children (P=0.0003) and in 3,301 subjects from the British 1958 Birth Cohort (P=0.0005). We systematically evaluated the relationships between markers of the 17q21 locus and transcript levels of genes in Epstein - Barr virus (EBV)-transformed lymphoblastoid cell lines from children in the asthma family panel used in our association study. The SNPs associated with childhood asthma were consistently and strongly associated (P < 10(-22)) in cis with transcript levels of ORMDL3, a member of a gene family that encodes transmembrane proteins anchored in the endoplasmic reticulum(3). The results indicate that genetic variants regulating ORMDL3 expression are determinants of susceptibility to childhood asthma.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62682/1/nature06014.pd
Theory of Inclusive B Decays
We present the theory of inclusive decays of hadrons containing a heavy quark
and discuss its most important applications to the decays of B mesons. We also
review the theoretical understanding of the hadronic parameters lambda_1 and
lambda_2 (or mu_pi^2 and mu_G^2) entering the heavy-quark expansion.Comment: 13 pages, 3 figures; to appear in the Proceedings of the 4th KEK
Topical Conference on Flavour Physics, KEK, Japan, October 199
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