1539910
A phenomenological study of photon production in low energy neutrino nucleon scattering
Low energy photon production is an important background to many current and future precision neutrino experiments. We present a phenomenological study of t-channel radiative corrections to neutral current neutrino nucleus scattering. After introducing the relevant processes and phenomenological coupling constants, we will explore the derived energy and angular distributions as well as total cross-section predictions along their estimated uncertainties. This is supplemented throughout with comments on possible experimental signatures and implications. We conclude with a general discussion of the analysis in the context of complimentary methodologies.
118402093
Minimally Allowed beta beta 0 nu Rates From Approximate Flavor Symmetries
Neutrinoless double beta decay ({beta}{beta}0{nu}) is the only realistic probe of Majorana neutrinos. In the standard scenario, dominated by light neutrino exchange, the process amplitude is proportional to m{sub ee} , the e - e element of the Majorana mass matrix. This is expected to hold true for small {beta}{beta}{nu} rates ({Gamma}{sub {beta}{beta}0{nu}}), even in the presence of new physics. Naively, current data allows for vanishing m{sub ee} , but this should be protected by an appropriate flavor symmetry. All such symmetries lead to mass matrices inconsistent with oscillation phenomenology. Hence, Majorana neutrinos imply nonzero {Gamma}{sub {beta}{beta}0{nu}}. I perform a spurion analysis to break all possible abelian symmetries that guarantee {Gamma}{sub {beta}{beta}0{nu}} = 0 and search for minimally allowed m{sub ee} values. Specifically, I survey 259 broken structures to yield m{sub ee} values and current phenomenological constraints under a variety of scenarios. This analysis also extracts predictions for both neutrino oscillation parameters and kinematic quantities. Assuming reasonable tuning levels, I find that m{sub ee} > 4 x 10{sup -6} eV at 99% confidence. Bounds below this value would indicate the Dirac neutrino nature or the existence of new light (eV-MeV scale) degrees of freedom that can potentially be probed elsewhere.more » This limit can be raised by improvements in neutrino parameter measurements, particularly of the reactor mixing angle, depending on the best fit parameter values. Such improvements will also significantly constrain the available model space and aid in future constructions.« less
12442898
What can we learn from neutrino electron scattering
Precision tests of the standard model are essential for constraining models of new physics. Neutrino-electron elastic scattering offers a clean probe into many electroweak effects that are complimentary to the more canonical measurements done at collider facilities. Such reactions are rare, even as compared with the already tiny cross sections for neutrino-nucleon scattering, and competitive precision measurements have historically been challenging to obtain. Because of new existing and proposed high-flux neutrino sources, this is about to change. We present a topical survey of precision measurements that can be done with neutrino-electron scattering in light of these new developments. Specifically, we consider four distinct neutrino sources: nuclear reactors, neutrino factories, beta beams, and conventional beams. For each source we estimate the expected future precision of several representative observables, including the weak mixing angle, neutrino magnetic moments, and potential leptonic ${Z}^{\ensuremath{'}}$ couplings. We find that future neutrino-electron scattering experiments should add nontrivially to our understanding of fundamental physics.
15898659
Semileptonic decays of light quarks beyond the Standard Model
We thank the Institute for Nuclear Theory at the University of Washington and the 
Aspen Center for Physics for their hospitality during the completion of this work. We thank 
Antonio Pich and Jorge Portoles for useful comments. M.G.-A. thanks A. Filipuzzi for useful 
comments and discussions and the LANL T-2 Group for its hospitality and partial support. 
This work has been supported in part by the EU RTN network FLAVIAnet [Contract No. 
MRTN-CT-2006-035482], by MICINN, Spain [Grants FPU No. AP20050910, FPA2007- 
60323 and Consolider-Ingenio 2010 Programme CSD2007-00042 -CPAN-] (M. G.-A.). This 
work was performed under the auspices of the National Nuclear Security Administration 
of the U.S. Department of Energy at Los Alamos National Laboratory under Contract No. 
DE-AC52-06NA25396, and was supported in part by the LANL LDRD program.
118491521
Model independent explorations of Majorana neutrino mass origins
The scale of neutrino mass generation may be too large to explore directly, but useful information may still be extracted from independent experimental channels. Here I survey various model independent probes of Majorana neutrino mass origins. An introduction to the concepts relevant to the analysis is followed by a discussion of the physical ranges of neutrino parameters within the context of standard and non-standard interactions. Armed with this, I move on to systematically analyze the properties of radiatively generated neutrino masses induced by nonrenormalizable lepton number violating effective operators of mass dimensions five through eleven. By fitting these to the observed light mass scale, I extract predictions for neutrino mixing as well as neutrinoless double beta decay, rare meson/tau decays and collider phenomenology. I find that many such models are already constrained by current data and many more will be probed in the near future. I then move on demonstrate the utility of a low scale seesaw mechanism via a viable sterile neutrino model that satisfies all oscillation data as well as solves problems associated with supernova kicks and heavy element nucleosynthesis. From this I extract predictions for tritium and neutrinoless double beta decay searches.
119115901
Pseudo-Dirac Neutrinos in the New Standard Model
The addition of gauge-singlet fermions to the standard model Lagrangian renders the neutrinos massive and allows one to explain all that is experimentally known about neutrino masses and lepton mixing by varying the values of the Majorana mass parameters M for the gauge singlets and the neutrino Yukawa couplings {lambda}. Here we explore the region of parameter space where M values are much smaller than the neutrino Dirac masses {lambda}v. In this region, neutrinos are pseudo-Dirac fermions. We find that current solar data constrain M values to be less than at least 10{sup -9} eV, and discuss the sensitivity of future experiments to tiny gauge-singlet fermion masses. We also discuss a useful basis for analyzing pseudo-Dirac neutrino mixing effects. In particular, we identify a simple relationship between elements of M and the induced enlarged mixing matrix and new mass-squared differences. These allow one to directly relate bounds on the new mass-squared differences to bounds on the singlet fermion Majorana masses.
120856316
The electromagnetic interaction of a massive spin one particle: some equivalence theorems and remarks
The minimal electromagnetic interaction is introduced into various free, quantum mechanical spin one formalisms, and it is found that the resulting theories are essentially equivalent. The situation does not prevail when, in addition, magnetic dipole or electric quadrupole interactions are considered. For simple such interactions in one formalism are found, in general, to be equivalent to structurally more complicated interactions in the other formalisms considered. Some known results on the acausal propagation of solutions of wave equations for a classical spin one particle in an external electromagnetic field are, with the aid of the above equivalence theorems, which are easily seen to apply to the classical case also, extended to include all the spin one formalisms considered herein.
122658441
On the possibility of breakdown of Lorentz invariance in the Takahashi-Umezawa quantization method
The Stuckelberg formalism for a massive spin-one field interacting with external potentials is quantized following the method of Takahashi and Umezawa. It is shown how the characteristic determinant of the field equations, which, in an earlier paper, was shown to have the same form as the Lee-yang determinant, for such a theory, determines the possibility of breakdown of Lorentz invariance in the procedure of the Takahashi-Umezawa quantization method.
119352130
Chandra multi-wavelength plane (ChaMPlane) survey: design and initial results
The Chandra Multiwavength Plane (ChaMPlane) Survey of the galactic plane incorporates serendipitous sources from selected Chandra pointings in or near the galactic plane (b 10-100), neutron stars and black holes (quiescent low mass X-ray binaries) to constrain their space densities and thus origin and evolution. Secondary objectives are to identify Be stars in high mass X-ray binaries and constrain their space densities, and to survey the H-R diagram for stellar coronal sources. A parallel optical imaging under the NOAO Long Term Survey program provides deep optical images using the Mosaic imager on the CTIO and KPNO 4-m telescopes. The 36′ × 36′ optical images (Hα, R, V and I) cover ∼ 5× the area of each enclosed Chandra ACIS FOV, providing an extended survey of emission line objects for comparison with Chandra. Spectroscopic followup of optical counterparts is then conducted, thus far with WIYN and Magellan. The X-ray preliminary results from both the Chandra and optical surveys will be presented, including logN-logS vs. galactic position (l,b) and optical identifications.
119095778
Initial optical results for the ChaMPlane Survey
We provide a brief description of the optical survey being conducted under the NOAO Long Term Surveys program in support of the Chandra Multiwavelength Plane (ChaMPlane) Survey (see paper by Grindlay et al. in this Volume). A representative photometry result is shown, along with spectroscopic followup.
122863150
Comments on the paper «Equivalence theorems for massive spin-one particles»