210 research outputs found
Large Direct CP Violation in B^0 -> pi^+ pi^- and an Enhanced Branching Ratio for B^0 -> pi^0 pi^0
Recent measurements of B^0 -> pi pi decays reveal two features that are in
conflict with conventional calculations: the channel B^0 (Bbar^0) -> pi^+ pi^-
shows a large direct CP-violating asymmetry, and the channel B^0 (B^0) -> pi^0
pi^0 has an unexpectedly high branching ratio. We show that both features can
be understood in terms of strong-interaction mixing of pi pi and D Dbar
channels in the isospin-zero state, an effect that is important because of the
large experimentally observed ratio Gamma(B^0 / Bbar^0 -> D^+ D^-) / Gamma (B^0
/ Bbar^0 -> pi^+ pi^-) approx. 50. Our dynamical model correlates the branching
ratios and the CP-violating parameters C and S, for the decays B^0 (Bbar^0) ->
pi^+ pi^-, B^0 (Bbar^0) -> pi^0 pi^0, B^0 (Bbar^0) -> D^+ D^- and B^0 (Bbar^0)
-> D^0 Dbar^0.Comment: 10 pages, 2 figures, 1 table; v2: Misprint corrected in Eq. (12),
second line: -a_m replaced by +a_m. To appear in Phys. Lett.
A model independent and rephase invariant parametrization of CP violation
The phenomenological description of the neutral B meson system is proposed in
terms of the fundamental CP-violating observables and within a rephasing
invariant formalism. This generic formalism can select the time-dependent and
time-integrated asymmetries which provide the basic tools to discriminate the
different kinds of possible CP-violating effects in dedicated experimental
B-meson facilities.Comment: 19 pages, Plain Te
Help-Seeking Attitudes and Distress Disclosure Among Syrian Refugees in Germany
Many refugees experience a wide range of mental health problems, but typically use mental health services less often than settled residents. Practical constraints like limited access to mental health care and language barriers largely account for this discrepancy. However, little is known about the psychological aspects explaining this difference in mental health service usage, like attitudes toward psychological help-seeking and the disclosure of distress. The present study compares German residents’ and Syrian refugees’ attitudes toward seeking professional psychological help ( N = 384). Refugees reported more depressive symptoms and functional impairment than residents. Crucially, refugees also held more negative attitudes toward professional psychological help-seeking than residents. These group differences in attitudes were to a large part mediated by distress disclosure. We conclude that it is important to achieve a thorough understanding of how to address help-seeking attitudes and to encourage distress disclosure to promote treatment of mental health issues among many refugees.</jats:p
Maple-Swarm: programming collective behavior for ensembles by extending HTN-planning
Programming goal-oriented behavior in collective adaptive systems is complex, requires high effort, and is failure-prone. If the system's user wants to deploy it in a real-world environment, hurdles get even higher: Programs urgently require to be situation-aware. With our framework Maple, we previously presented an approach for easing the act of programming such systems on the level of particular robot capabilities. In this paper, we extend our approach for ensemble programming with the possibility to address virtual swarm capabilities encapsulating collective behavior to whole groups of agents. By using the respective concepts in an extended version of hierarchical task networks and by adapting our self-organization mechanisms for executing plans resulting thereof, we can achieve that all agents, any agent, any other set of agents, or a swarm of agents execute (swarm) capabilities. Moreover, we extend the possibilities of expressing situation awareness during planning by introducing planning variables that can get modified at design-time or run-time as needed. We illustrate the possibilities with examples each. Further, we provide a graphical front-end offering the possibility to generate mission-specific problem domain descriptions for ensembles including a lightweight simulation for validating plans
Muscular anatomy of an entoproct creeping-type larva reveals extraordinary high complexity and potential shared characters with mollusks
GARIMAS 1 - GAlapagos RIft MAssive Sulphides : Cruise 32 of MS SONNE, 09.05.-09.07.1984 ; cruise report
Optimization of the design of OMNIS, the observatory of multiflavor neutrinos from supernovae
A Monte Carlo code has been developed to simulate the operation of the
planned detectors in OMNIS, a supernova neutrino observatory. OMNIS will detect
neutrinos originating from a core collapse supernova by the detection of
spalled neutrons from Pb- or Fe-nuclei. This might be accomplished using
Gd-loaded liquid scintillator. Results for the optimum configuration for such
modules with respect to both neutron detection efficiency and cost efficiency
are presented. Careful consideration has been given to the expected levels of
radioactive backgrounds and their effects. The results show that the amount of
data to be processed by a software trigger can be reduced to the <10kHz region
and a neutron, once produced in the detector, can be detected and identified
with an efficiency of >30%.Comment: Elsevier preprint; 29 pages, 23 figure
Are B to PI K CP-asymmetries quantized ?
Search for patterns in the numerous B-decay modes now available is necessary
in order to test the Cabibbo-Kobayashi-Maskawa theory of CP-violation. In
particular, the well-structured pattern of B to PI K branching ratios may lead
to a quantized spectrum for direct CP-asymmetries, providing in this way a
rather unique opportunity to discriminate between strong final state
interaction models.Comment: Latex, 12 pages, 3 ps figures. Few comments added, final version to
appear in Eur.Phys.J.
Inelastic Final-State Interactions and Two-body Hadronic B decays into Single-Isospin channels
The role of inelastic final-state interactions in CP asymmetries and
branching ratios is investigated in certain chosen single isospin two-body
hadronic B decays. Treating final-state interactions through Pomeron and Regge
exchanges, we demonstrate that inelastic final state interactions could lead to
sizeable effects on the CP asymmetry.Comment: 23 pages, Latex, 1 eps-figur
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