77,453 research outputs found
CP Violation: Past, Present, and Future
We discuss the history of CP violation and its manifestations in kaon
physics, its explanation in terms of phases of the Cabibbo-Kobayashi-Maskawa
matrix describing charge-changing weak quark transitions, predictions for
experiments involving mesons, and the light it can shed on physics beyond
the Standard Model.Comment: 13 pages, LaTeX, 8 figures, Invited talk presented at XXI Brazilian
National Meeting on Particles and Fields, Sao Lourenco, Minas Gerais, October
23--26, 2000, proceedings to be published in a special issue of the Brazilian
Journal of Physics. Further small changes in two figure captions and
acknowledgment
Self-Correcting Broadcast in Distributed Hash Tables
We present two broadcast algorithms that can be used on top of distributed hash tables (DHTs) to perform group communication and arbitrary queries. Unlike other P2P group communication mechanisms, which either embed extra information in the DHTs or use random overlay networks, our algorithms take advantage of the structured DHT overlay networks without maintaining additional information. The proposed algorithms do not send any redundant messages. Furthermore the two algorithms ensure 100% coverage of the nodes in the system even when routing information is outdated as a result of dynamism in the network. The first algorithm performs some correction of outdated routing table entries with a low cost of correction traffic. The second algorithm exploits the nature of the broadcasts to extensively update erroneous routing information at the cost of higher correction traffic. The algorithms are validated and evaluated in our stochastic distributed-algorithms simulator
CP,T and/or CPT Violations in the K0-K0bar System --Implications of the KTeV,NA48 and CPLEAR Results
Possible violation of CP, T and/or CPT symmetries in the \ko-\kob system
is studied from a phenomenological point of view. For this purpose, we first
introduce parameters which represent violation of these symmetries in mixing
parameters and decay amplitudes in a convenient and well-defined way and,
treating these parameters as small, derive formulas which relate them to the
experimentally measured quantities. We then perform numerical analyses, with
the aid of the Bell-Steinberger relation, to derive constraints to these
symmetry-violating parameters, firstly paying particular attention to the
results reported by KTeV Collaboration and NA48 Collaboration, and then with
the results reported by CPLEAR Collaboration as well taken into account. A case
study, in which either CPT symmetry or T symmetry is assumed, is also carried
out. It is demonstrated that CP and T symmetries are violated definitively at
the level of 10^{-4} in decays and presumably at the level of 10^{-3} in
the \ko-\kob mixing, and that the Bell-Steinberger relation helps us to
establish CP and T violations being definitively present in the \ko-\kob
mixing and to test CPT symmetry to a level of 10^{-4} ~ 10^{-5}.Comment: 21 pages, 1 figure
Present and Future Aspects of CP Violation
This series of five lectures describes aspects of CP violation, emphasizing
its description within the standard electroweak model. After discussing the
kaon system, the only place in which CP violation has been seen so far, we turn
to the leading contender for the effect, complex phases in the
Cabibbo-Kobayashi-Maskawa (CKM) matrix. A number of suggestions are made for
improved tests of the standard picture. Hadrons containing quarks play a
key role in this program, and are discussed separately. We also mention a
number of non-standard and speculative aspects of CP violation, including
alternatives to the CKM description, direct tests of time reversal invariance,
and baryogenesis.Comment: 58 pages, latex, 14 uuencoded figures sent separatel
B Physics - A Theoretical Review
This overview of what we can hope to learn from high-statistics experiments
in B physics in the next few years includes: (a) a review of parameters of the
Cabibbo-Kobayashi-Maskawa (CKM) Matrix; (b) direct determination of magnitudes
of CKM elements; (c) forthcoming information from studies of kaons; (d) CP
violation in B decays; (e) aspects of rate measurements; (f) the role of
charm-anticharm annihilation; (g) remarks on tagging; and (h) effects beyond
the standard model.Comment: 23 pages, latex, 4 figures, further corrections to reference
Status of three-neutrino oscillation parameters, circa 2013
The standard three-neutrino (3nu) oscillation framework is being increasingly
refined by results coming from different sets of experiments, using neutrinos
from solar, atmospheric, accelerator and reactor sources. At present, each of
the known oscillation parameters [the two squared mass gaps (delta m^2, Delta
m^2) and the three mixing angles (theta_12}, theta_13, theta_23)] is dominantly
determined by a single class of experiments. Conversely, the unknown parameters
[the mass hierarchy, the theta_23 octant and the CP-violating phase delta] can
be currently constrained only through a combined analysis of various
(eventually all) classes of experiments. In the light of recent new results
coming from reactor and accelerator experiments, and of their interplay with
solar and atmospheric data, we update the estimated N-sigma ranges of the known
3nu parameters, and revisit the status of the unknown ones. Concerning the
hierarchy, no significant difference emerges between normal and inverted mass
ordering. A slight overall preference is found for theta_23 in the first octant
and for nonzero CP violation with sin delta < 0; however, for both parameters,
such preference exceeds 1 sigma only for normal hierarchy. We also discuss the
correlations and stability of the oscillation parameters within different
combinations of data sets.Comment: Updated and revised version, accepted for publication in PRD. The
analysis includes the latest (March 2014) T2K disappearance data: all the
figures and the numerical results have been updated, and parts of the text
have been revised accordingl
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