NEUTRINOS, FLAVOR PHYSICS, AND PRECISION COSMOLOGY: Fourth Tropical Workshop on Particle Physics and Cosmology
689(2003); http://dx.doi.org/10.1063/1.1627723View Description Hide Description
The Radio Ice Cherenkov Experiment is an ultra‐high energy neutrino detector at the South Pole. In this contribution we motivate the search for ultra‐high energy neutrinos by considering the astrophysical objects which are expected to emit neutrinos. We describe the philosophy behind using radio receivers to detect the Cherenkov radiation produced when ultra‐high energy neutrinos interact in a dense medium and outline the analysis path for obtaining limits on the ultra‐high energy neutrino flux.
689(2003); http://dx.doi.org/10.1063/1.1627725View Description Hide Description
The MiniBooNE experiment is designed to verify the possibility that the excess of v̄e observed by the LSND experiment is due to neutrino oscillations. MiniBooNE commenced data taking on September 1, 2003. Over 140,000 events have been recorded with a positive particle focus, i.e. in neutrino mode. While the analysis is vigorously underway and while detector performance appears to be satisfactory, no physics results are reported due to the ‘blind’ analysis approach being taken by the collaboration. Physics results are expected to be released sometime between autumn of 2004 and summer of 2005.
689(2003); http://dx.doi.org/10.1063/1.1627726View Description Hide Description
The K2K, the KEK to Kamioka long baseline neutrino oscillation experiment, observes evidences of neutrino oscillation: a reduction of muon neutrinos together with a distortion of the energy spectrum. Fifty six beam‐originated neutrino events are observed in Super‐Kamiokande with an expectation of events. Among those events, twenty‐nine single‐ring muon‐like events are used to reconstruct the neutrino energy. The measured energy spectrum better matches with the expected one with oscillation. The probability of no oscillation is calculated to be less than 1 %. In a two flavor oscillation scenario, the allowed Δm 2 region at sin22θ = 1 is between 1.5 and 3.9 × 10−3 eV2 at the 90 % C.L. The result at K2K is consistent with the oscillation of atmospheric neutrinos reported by Super‐Kamiokande collaboration.
689(2003); http://dx.doi.org/10.1063/1.1627727View Description Hide Description
There is a tremendous potential for neutrinos to yield valuable new information about strongly interacting systems. Here we provide a taste of this potential, beginning with the existence of a rigorous sum rule for the proton and neutron spin structure functions based on the measurement of the flavor singlet axial charge of the nucleon. We also comment on the NuTeV report of a 3σ deviation of the value of sin2θ W measured in neutrino (and anti‐neutrino) scattering from that expected within the Standard Model.
689(2003); http://dx.doi.org/10.1063/1.1627728View Description Hide Description
In this talk we review the results on neutrino propagation under external magnetic fields. We concentrate on the effects of strong magnetic fields in neutral media. It is shown that the neutrino energy density get a magnetic contribution in the strong‐field, one‐loop approximation, which is linear in the Fermi coupling constant as in the charged medium. It is analyzed how this correction produces a significant oscillation resonance between electron‐neutrinos and the other two active flavors, as well as with sterile neutrinos. The found resonant level‐crossing condition is highly anisotropic. Possible cosmological applications are discussed. Effects due to primordial hypermagnetic fields on neutrinos propagating in the symmetric phase of the electroweak model are also presented. At sufficiently strong hypermagnetic fields, B ⩾ T 2, the neutrino energy is found to be similar to that of a massless charged particle with one‐degree of freedom.
689(2003); http://dx.doi.org/10.1063/1.1627730View Description Hide Description
This is a review of the time‐independent measurements using semileptonic and rare B meson decays at the Babar, Belle and CLEO experiments. These measurements allow the constraint of the Unitarity Triangle in the Standard Model and to search for hints of new physics. At first, we summarize the measurements of Vcb and Vub using semileptonic decays. Then we review results on rare B decays, which include purely leptonic, radiative, B → D (*) K (*), charmless hadronic, and electroweak penguin decays.
689(2003); http://dx.doi.org/10.1063/1.1627731View Description Hide Description
High energy nucleus‐nucleus collisions are used for the search for the quark‐gluon plasma, a state of matter predicted by lattice QCD. Results from Au+Au, p+p and d+Au collisions at and 200 GeV are presented. The temperature, size, energy and parton density of the system are determined. The early phase of the collision t⩽1 fm/c can be tested tested in particular by hard parton scattering (i.e. jet production) and production of heavy particles, which requires a high temperature T⩾300 MeV. Comparisons to the primordial phase of the universe are made.
689(2003); http://dx.doi.org/10.1063/1.1627732View Description Hide Description
Based on the QCD factorization approach we analyse the branching ratios for the channel B → ρπ. From the comparisons with experimental data provided by CLEO, BELLE and BABAR we constrain the form factor and propose boundaries for this form factor depending on the CKM matrix element parameters ρ and η.
689(2003); http://dx.doi.org/10.1063/1.1627733View Description Hide Description
The status of Run II of the Tevatron and the D∅ experiment are reviewed and recent results on the preparations for measurement of CP violation in B meson decays and searches for the lightest SUSY particle and evidence for large extra dimensions are presented. Whilst signals have yet to be established in these areas, the results shown illustrate the potential of the D∅ experiment to make measurements of cosmological significance in the next few years prior to the turn‐on of the LHC.
689(2003); http://dx.doi.org/10.1063/1.1627734View Description Hide Description
Some theoretical aspects of B physics are reviewed. These include a brief recapitulation of information on weak quark transitions as described by the Cabibbo‐Kobayashi‐Maskawa (CKM) matrix, descriptions of CP asymmetries in B decays to CP eigenstates and to self‐tagging modes, a discussion of final‐state phases in B and charm decays, some topics on Bs properties and decays, prospects for unusual excited B states opened by discovery of some narrow cs̄ resonances, and the search for heavier Q = 1/3 quarks predicted in some extended grand unified theories.
689(2003); http://dx.doi.org/10.1063/1.1627735View Description Hide Description
At this time the search for most of the mass in the universe has reached a very exciting stage. There is evidence for detection, but also evidence against such a discovery. A new generation of experiments has started operating, and big improvements in sensitivity should be available soon. This review of experiments to detect dark matter will not be comprehensive, as this is a very active field, but rather it will concentrate on those developments which appear at this time to be the leading ones.
689(2003); http://dx.doi.org/10.1063/1.1627736View Description Hide Description
Cosmologists have developed a phenomenally successful picture of structure in the universe based on the idea that the universe expanded exponentially in its earliest moments. There are three pieces of evidence for this exponential expansion — inflation — from observations of anisotropies in the cosmic microwave background. First, the shape of the primordial spectrum is very similar to that predicted by generic inflation models. Second, the angular scale at which the first acoustic peak appears is consistent with the flat universe predicted by inflation. Here I describe the third piece of evidence, perhaps the most convincing of all: the phase coherence needed to account for the clear peak/trough structure observed by the WMAP satellite and its predecessors.
689(2003); http://dx.doi.org/10.1063/1.1627737View Description Hide Description
By studying the present cosmological data, particularly on CMB, SNeIA and LSS, we find that the future fate of the universe, for simple linear models of the dark energy equation‐of‐state, can vary between the extremes of (I) a divergence of the scale factor in as little as 7 Gyr; (II) an infinite lifetime of the universe with dark energy dominant for all future time; (III) a disappearing dark energy where the universe asymptotes as t → ∞ to a(t) ∼ t 2/3 i.e. matter domination. Precision cosmological data hint that a dark energy with equation of state w = P/ρ < −1 and hence dubious stability is viable. Here we discuss for any w nucleation from Λ > 0 to Λ = 0 in a first‐order phase transition. The critical radius is argued to be at least of galactic size and the corresponding nucleation rate glacial, thus underwriting the dark energy’s stability and rendering remote any microscopic effect.