Scholarly Articles, Institute for Particle, Nuclear and Astronomical Sciences (IPNAS)
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- Constraints on New Physics from Long Baseline Neutrino Oscillation ExperimentsHonda, M.; Kao, Y.; Okamura, Naotoshi; Pronin, A.; Takeuchi, Tatsu (2007)New physics beyond the Standard Model can lead to extra matter effects on neutrino oscillation if the new interactions distinguish among the three flavors of neutrino. In a previous paper [1], we argued that a long-baseline neutrino oscillation experiment in which the Fermilab-NUMI beam in its high-energy mode [2] is aimed at the planned Hyper-Kamiokande detector [3] would be capable of constraining the size of those extra effects, provided the vacuum value of sin2 2θ23 is not too close to one. In this paper, we discuss how such a constraint would translate into limits on the coupling constants and masses of new particles in various models. The models we consider are: models with generation distinguishing Z′s such as topcolor assisted technicolor, models containing various types of leptoquarks, R-parity violating SUSY, and extended Higgs sector models. In several cases, we find that the limits thus obtained could be competitive with those expected from direct searches at the LHC. In the event that any of the particles discussed here are discovered at the LHC, then the observation, or non-observation, of their matter effects could help in identifying what type of particle had been observed.
- Single-Coupling Bounds on R-parity violating Supersymmetry, an updateKao, Y.; Takeuchi, Tatsu (2009)We update the single-coupling bounds on R-parity violating supersymmetry using the most up to date data as of October 2009. In addition to the data listed in the 2009 Review of Particle Properties [1], we utilize a new determination of the weak charge of cesium-133 [2], and preliminary τ -decay branching fractions from Babar [3]. Analysis of semileptonic D-decay is improved by the inclusion of experimentally measured form-factors into the calculation of the Standard Model predictions.
- Constraints on R-parity violation from recent Belle/Babar dataKao, Y.; Takeuchi, Tatsu (2009)
- Ratchet Model of BaryogenesisTakeuchi, Tatsu; Minamizaki, A.; Sugamoto, A. (World Scientific, 2011-01-01)
- Position and momentum uncertainties of a particle in a V-shaped potential under the minimal length uncertainty relationLewis, Zachary; Roman, Ahmed; Takeuchi, Tatsu (World Scientific, 2015-12-20)
- Running of oscillation parameters in matter with flavor-diagonal non-standard interactions of the neutrinoAgarwalla, S. K.; Kao, Y.; Saha, D.; Takeuchi, Tatsu (Springer, 2015-11-05)In this article we unravel the role of matter effect in neutrino oscillation in the presence of lepton-flavor-conserving, non-universal non-standard interactions (NSI’s) of the neutrino. Employing the Jacobi method, we derive approximate analytical expressions for the effective mass-squared differences and mixing angles in matter. It is shown that, within the effective mixing matrix, the Standard Model (SM) W-exchange interaction only affects θ12 and θ13, while the flavor-diagonal NSI’s only affect θ23. The CP-violating phase δ remains unaffected. Using our simple and compact analytical approximation, we study the impact of the flavor-diagonal NSI’s on the neutrino oscillation probabilities for various appearance and disappearance channels. At higher energies and longer baselines, it is found that the impact of the NSI’s can be significant in the νµ → νµ channel, which can probed in future atmospheric neutrino experiments, if the NSI’s are of the order of their current upper bounds. Our analysis also enables us to explore the possible degeneracy between the octant of θ23 and the sign of the NSI parameter for a given choice of mass hierarchy in a simple manner.
- Lifetimes of the Heavy Neutral Leptons in the Okamura ModelPronin, A.; Takeuchi, Tatsu (2006)We study the lifetimes of TeV-scale heavy neutral leptons (Majorana neutrinos) that appear in a model suggested by Okamura et al. [2]. We develop a convenient way to parametrize the neutrino mass texture of the model, and illustrate our method by calculating the mass spectrum, decay widths, and lifetimes of the heavy particles over the entire parameter space. From the mass spectrum, we find that for most of the parameter space, only two-body decays are relevant in the calculation of the lifetime, with typical values falling in the range of 10−26 to 10−24 seconds. If the particles discussed here are created at colliders, their lifetimes are short enough for them to decay inside the detector, while long enough to lead to a narrow peak in the invariant mass spectrum of the decay products. However, an analysis by Dicus, Karatas, and Roy [16] suggests that they may be difficult to observe at the LHC
- A Simple parameterization of matter effects on neutrino oscillationsHonda, M.; Kao, Y.; Okamura, Naotoshi; Takeuchi, Tatsu (2006)We present simple analytical approximations to matter-effect corrected effective neutrino mixing-angles and effective mass-squared-differences. The expressions clarify the dependence of oscillation probabilities in matter to the mixing angles and mass-squared-differences in vacuum, and are useful for analyzing long-baseline neutrino oscillation experiments.
- Matter Effect on Neutrino Oscillations from the violation of Universality in Neutrino Neutral Current InteractionsHonda, M.; Okamura, Naotoshi; Takeuchi, Tatsu (2006)The violation of lepton-flavor-universality in the neutrinoZ interactions can lead to extra matter effects on neutrino oscillations at high energies, beyond that due to the usual charged-current interaction of the electron-neutrino. We show that the dominant effect of the violation is a shift in the effective value of θ23. This is in contrast to the dominant effect of the charged-current interaction which shifts θ12 and θ13. The shift in θ23 will be difficult to observe if the value of sin2(2θ23) is too close to one. However, if the value of sin2(2θ23) is as small as 0.92, then a Fermilab →Hyper-Kamiokande experiment can potentially place a constraint on universality violation at the 1% level after 5 years of data taking.
- The NuTev anomaly, neutrino mixing, and a heavy HiggsTakeuchi, Tatsu (2002)
- The W mass and the U parameterTakeuchi, Tatsu; Loinaz, William; Okamura, Naotoshi; Wijewardhana, L. C. R. (2003)
- Constraining new physics with vertex correctionsTakeuchi, Tatsu; Lebedev, O.; Loinaz, William (1999)
- Indirect probes of new physicsHewett, J. L.; Takeuchi, Tatsu; Thomas, S. D. (World Scientific, 1996)We summarize the indirect effects of new physics in a variety of processes. We consider precision electroweak measurements, the g−2 of the muon, rare decays, meson mixing, CP violation, lepton number violating interactions, double beta decay, and the electric dipole moments of atoms, molecules, and the neutron. We include discussions of both model independent and dependent analyses where applicable.
- The Status of the electroweak sector of the standard modelTakeuchi, Tatsu (1995)
- An analysis of nonoblique corrections to the Zb¯b vertexTakeuchi, Tatsu; Grant, Aaron K.; Rosner, Jonathan L. (1994)We present a model–independent analysis of the Zb¯b vertex, with the aim of constraining contributions of new physics to the left- and right–handed couplings of the b. We find that the left–handed coupling of the b is quite narrowly constrained by present data, but that the right–handed coupling is still largely unconstrained.
- The difficulties involved in calculating $δρ$Takeuchi, Tatsu; Grant, Aaron K.; Worah, Mihir P. (1995-04)We discuss the difficulties that arise when one tries to calculate $\delta\rho$ using dispersion relations.
- Transient pulses from exploding primordial black holes as a signature of an extra dimensionKavic, Michael; Simonetti, John H.; Cutchin, Sean E.; Ellingson, Steven W.; Patterson, Cameron D. (IOP, 2008-11-01)An evaporating black hole in the presence of an extra spatial dimension would undergo an explosive phase of evaporation. We show that such an event, involving a primordial black hole, can produce a detectable, distinguishable electromagnetic pulse, signaling the existence of an extra dimension of size L ∼ 10−18 − 10−20 m. We derive a generic relationship between the Lorentz factor of a pulse-producing “fireball” and the TeV energy scale. For an ordinary toroidally compactified extra dimension, transient radio-pulse searches probe the electroweak energy scale (∼0.1 TeV), enabling comparison with the Large Hadron Collider.
- Quantum Gravity, Dynamical Energy-Momentum Space and Vacuum EnergyChang, Lay Nam; Minic, Djordje; Takeuchi, Tatsu (World Scientific, 2010-11-01)We argue that the combination of the principles of quantum theory and general relativity allow for a dynamical energy-momentum space. We discuss the freezing of vacuum energy in such a dynamical energy-momentum space and present a phenomenologically viable seesaw formula for the cosmological constant in this context.
- Hydrogen-atom spectrum under a minimal-length hypothesisBenczik, S. Z.; Chang, Lay Nam; Minic, Djordje; Takeuchi, Tatsu (American Physical Society, 2005-07-01)
- An evaluation of the analytic continuation by duality techniqueTakeuchi, Tatsu; Goonetileke, L. C.; Ignjatovic, S. R.; Wijewardhana, L. C. R. (1997)In Nucl. Phys. B391 (1993) 127, the value of the oblique correction parameter S for walking technicolor theories was estimated using a technique called Analytic Continuation by Duality (ACD). We apply the ACD technique to the perturbative vacuum polarization function and find that it fails to reproduce the well known result S=1/6\pi. This brings into question the reliability of the ACD technique and the ACD estimate of S.
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