16,983 research outputs found
New Charm Results from Focus
New results from the photoproduction experiment FOCUS are reported: Dalitz
plot analysis, semileptonic form factor ratios and excited meson spectroscopy.Comment: 8 pages, 5 figures, Frascati preprint style lnfprep.sty (included).
Presented by S.Bianco at the 18th Rencontres de Physique de la Vallee d'Aoste
29 February-6 March, La Thuile, Vallee d'Aoste, Italy. Frascati preprint
LNF-04/14(P), Fermilab preprint FERMILAB-CONF-04-372-
Prospect of D0 mixing and CPV at LHCb
Precision measurements in charm physics offer a window into a unique sector
of potential New Physics interactions. LHCb is poised to become a world leading
experiment for charm studies, recording enormous statistics with a detector
tailored for flavor physics. This article presents recent charm CPV and mixing
studies from LHCb, including LHCb's first CP asymmetry measurement with 37
inverse pb of data collected in 2010. The difference of the CP asymmetries of
D0 decays to the K-K+ and \pi-\pi+ final states is determined to be \Delta
A_{CP} = (-0.28 +/- 0.70 +/- 0.25)%. Significant updates to the material
presented at the 4th International Workshop on Charm Physics are included.Comment: 5 pages, 4 figures. Submitted to the proceedings of the 4th
International Workshop on Charm Physics (Charm2010), Beijing, Chin
Space-time nature of causality
Peer reviewedPostprintPublisher PD
Practical Algorithms for Multicast Support in Input Queues Switches
Abstract â This paper deals with multicast flow support in N Ă N Input Queued switch architectures. A practical approach to support multicast traffic is presented, assuming that O(N) queues are available at each input port. The focus is on dynamic queueing policies, where, at each input port, multicast flows are assigned to one among the available queues when flows become active: flows are assigned to queues according to switch queue status and, possibly, to flow information. We discuss queueing assignments, scheduling algorithms and flow activity definition models. We explain why dynamic queueing disciplines may outperform static policies, and we show that, even in the most favorable conditions for static policies, they provide comparable performance. I
Effects of Littlest Higgs model in rare D meson decays
A tree-level flavor changing neutral current in the up-like quark sector
appears in one of the variations of the Littlest Higgs model. We investigate
the effects of this coupling in the D+ -> pi+ l+ l- and D0 -> rho0 l+ l-
decays, which are the most appropriate candidates for the experimental studies.
However, the effects are found to be too small to be observed in the current
and the foreseen experimental facilities. These decays are still dominated by
the standard model long-distance contributions, which are reevaluated based on
the new experimental input.Comment: 13 pages, 3 figures; new constraint on scale f taken into account and
effects on charm meson decays recalculate
On the physical processes which lie at the bases of time variability of GRBs
The relative-space-time-transformation (RSTT) paradigm and the interpretation
of the burst-structure (IBS) paradigm are applied to probe the origin of the
time variability of GRBs. Again GRB 991216 is used as a prototypical case,
thanks to the precise data from the CGRO, RXTE and Chandra satellites. It is
found that with the exception of the relatively inconspicuous but
scientifically very important signal originating from the initial ``proper
gamma ray burst'' (P-GRB), all the other spikes and time variabilities can be
explained by the interaction of the accelerated-baryonic-matter pulse with
inhomogeneities in the interstellar matter. This can be demonstrated by using
the RSTT paradigm as well as the IBS paradigm, to trace a typical spike
observed in arrival time back to the corresponding one in the laboratory time.
Using these paradigms, the identification of the physical nature of the time
variablity of the GRBs can be made most convincingly. It is made explicit the
dependence of a) the intensities of the afterglow, b) the spikes amplitude and
c) the actual time structure on the Lorentz gamma factor of the
accelerated-baryonic-matter pulse. In principle it is possible to read off from
the spike structure the detailed density contrast of the interstellar medium in
the host galaxy, even at very high redshift.Comment: 11 pages, 5 figure
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