We reexamine the possibility of explaining the latest Super-Kamiokande atmospheric neutrino data ... more We reexamine the possibility of explaining the latest Super-Kamiokande atmospheric neutrino data including the upward going muon data by means of flavor-changing induced massless neutrino oscillations. We show that the energy independence of such flavor-changing coversion clearly leads to incompatibility between the upward going passing muons and the other samples, unless the flux of passing muons is larger than expected.
In this work we study the signals of these leptoquarks at the CERN Large Hadron Collider and comp... more In this work we study the signals of these leptoquarks at the CERN Large Hadron Collider and compare them with the ones expected in supersymmetric models.
If unparticle operators couple to fermions they may induce long-range forces that can cause great... more If unparticle operators couple to fermions they may induce long-range forces that can cause great changes in the neutrino evolution in matter, in particular, in the Sun. Current data from solar neutrino experiments and KamLAND allow us to place stringent limits on those new interactions.
We investigate the potential of a future kilometer-scale neutrino telescope, such as the proposed... more We investigate the potential of a future kilometer-scale neutrino telescope, such as the proposed IceCube detector in the South Pole, to measure and disentangle the yet unknown components of the cosmic neutrino flux, the prompt atmospheric neutrinos coming from the decay of charmed particles and the extra-galactic neutrinos in the 10 TeV to 1 EeV energy range. Assuming a power law type spectra, dφν/dEν˜αEβν, we quantify the discriminating power of the IceCube detector and discuss how well we can determine magnitude (α) as well as slope (β) of these two components of the high energy neutrino spectrum, taking into account the background coming from the conventional atmospheric neutrinos.
We have investigated the possibility of discerning mass from flavor changing neutrino interaction... more We have investigated the possibility of discerning mass from flavor changing neutrino interactions induced $\nu_\mu \to \nu_\tau$ oscillations in the long baseline neutrino experiments K2K and MINOS. We have found that for virtually any value of the flavor conserving parameter $\epsilon^\prime$ it will be possible to, independently, distinguish these two mechanisms at K2K, if the flavor changing parameter $\epsilon$ is in the range $\epsilon \gsim 0.77$, and at MINOS, if $\epsilon \gsim 0.2$. Moreover, if K2K measures a depletion of the expected $\nu_\mu$ flux then MINOS will either observe or discard completely flavor changing neutrino oscillations.
We find an exact analytic solution for the time evolution of a three Dirac neutrino system adiaba... more We find an exact analytic solution for the time evolution of a three Dirac neutrino system adiabatically oscillating in matter, constructing explicitly the relevant $3\times 3$ mixing matrix in matter. Using this result we investigate the solar neutrino data in a scenario where the neutrino masses are such that $m_1\alt m_2\ll m_3$, taking into account several phenomenological constraints on neutrino mixing angles and masses. A solution of the solar neutrino problem for large values of the parameter $\delta m^2=m_2^2-m_1^2$ which are not usually associated with a resonance is found. This is an essentially three-generation effect.
This is a crash course that aims to serve as a guide for students who wish to learn the Monte Car... more This is a crash course that aims to serve as a guide for students who wish to learn the Monte Carlo Simulation Technique and its applications to particle physics. The general ideas about the Monte Carlo Method of Integration is discussed but emphasis is given to the use of Monte Carlo to theoretically predict the value of observables and compare the theoretical prediction with experimental data.
Assuming that neutrinos are Majorana particles, in a three-generation framework, current and futu... more Assuming that neutrinos are Majorana particles, in a three-generation framework, current and future neutrino oscillation experiments can determine six out of the nine parameters which fully describe the structure of the neutrino mass matrix. We try to clarify the interplay among the remaining parameters, the absolute neutrino mass scale and two CP violating Majorana phases, and how they can be accessed by future neutrinoless double beta (0νββ) decay experiments, for the normal as well as for the inverted order of the neutrino mass spectrum. Assuming the oscillation parameters to be in the range presently allowed by atmospheric, solar, reactor, and accelerator neutrino experiments, we quantitatively estimate the bounds on m0, the lightest neutrino mass, that can be inferred if the next generation 0νββ decay experiments can probe the effective Majorana mass (mee) down to ~1 meV. In this context we conclude that in the case that neutrinos are Majorana particles, (a) if m0>~300 meV, i.e., within the range directly attainable by future laboratory experiments as well as astrophysical observations, then mee>~30 meV must be observed, (b) if m0<300 meV, results from future 0νββ decay experiments combined with stringent bounds on the neutrino oscillation parameters, especially the solar ones, will place much stronger limits on the allowed values of m0 than these direct experiments. For instance, if a positive signal is observed around mee=10 meV, we estimate 3<~m0/meV<~65 at 95% C.L.; on the other hand, if no signal is observed down to mee=10 meV, then m0<~55 meV at 95% C.L.
We perform a detailed analysis of the capabilities of the MINOS, ICARUS and OPERA experiments to ... more We perform a detailed analysis of the capabilities of the MINOS, ICARUS and OPERA experiments to measure neutrino oscillation parameters at the atmospheric scale with their data taken separately and in combination. MINOS will determine Δm232 and sin22θ23 to within 10% at the 99% C.L. with 10 kton-years of data. While no one experiment will determine sin22θ13 with much precision, if its value lies in the combined sensitivity region of the three experiments, it will be possible to place a lower bound of O(0.01) at the 95% C.L. on this parameter by combining the data from the three experiments. The same bound can be placed with a combination of MINOS and ICARUS data alone.
Based on the work by N. Cipriano Ribeiro et. al., JHEP 0712, 002 (2007) [arXiv:0709.1980 [hep-ph]... more Based on the work by N. Cipriano Ribeiro et. al., JHEP 0712, 002 (2007) [arXiv:0709.1980 [hep-ph]], in this poster, we discuss the potential of a neutrino factory to probe the so called non-standard neutrino interactions (NSI) with matter, which may exist as a low-energy manifestation of physics beyond the Standard Model. Using the appearance modes νe rangle νμ/erangleμ, we demonstrate how powerful is the setting of two detectors with different baselines, one at L = 3000 km and the other at L = 7000 km, where the latter is nearly at the magic baseline which is known to have a great sensitivity to matter density determination. Assuming the effects of NSI at the production and the detection are negligible, we study the impact of NSI in the neutrino propagation, and determine the sensitivity to NSI parameters, epsilonαβ, and at the same time discuss how the determination of θ13 and δ is affected. We found that the effect of 'synergy' of combing two detectors is significant, providing high sensitivity to NSI parameters and powerful enough to resolve the confusion between θ13 and the NSI effect. We obtain, for example, at sin2 2θ13 = 10-4, the sensitivity of |epsiloneτ| a few x 10-3 at 3σ CL for 2 degrees of freedom, without loosing much the sensitivity to θ13 and δ. Our results imply that neutrino factory can be a hunting machine for NSI while keeping its primary function of performing precision measurements of the lepton mixing parameters.
If the lepton mixing angle θ23 is not maximal, there arises a problem of ambiguity in determining... more If the lepton mixing angle θ23 is not maximal, there arises a problem of ambiguity in determining θ23 due to the existence of two degenerate solutions, one in the first and the other in the second octant. We discuss an experimental strategy for resolving the θ23 octant degeneracy by combining reactor measurement of θ13 with accelerator νμ disappearance and νe appearance experiments. The robustness of the θ23 degeneracy and the difficulty in lifting it only by accelerator experiments with conventional νμ (and ν¯μ) beams are demonstrated by analytical and numerical treatments. Our method offers a way to overcome the difficulty and can resolve the degeneracy between solutions sin2θ23=0.4 and sin2θ23=0.6 if sin22θ13≳0.05 at 95% CL by assuming the T2K phase II experiment and a reactor measurement with an exposure of 10 GW·kt·yr. The dependence of the resolving power of the octant degeneracy on the systematic errors of reactor experiments is also examined.
We reexamine the possibility of explaining the latest Super-Kamiokande atmospheric neutrino data ... more We reexamine the possibility of explaining the latest Super-Kamiokande atmospheric neutrino data including the upward going muon data by means of flavor-changing induced massless neutrino oscillations. We show that the energy independence of such flavor-changing coversion clearly leads to incompatibility between the upward going passing muons and the other samples, unless the flux of passing muons is larger than expected.
In this work we study the signals of these leptoquarks at the CERN Large Hadron Collider and comp... more In this work we study the signals of these leptoquarks at the CERN Large Hadron Collider and compare them with the ones expected in supersymmetric models.
If unparticle operators couple to fermions they may induce long-range forces that can cause great... more If unparticle operators couple to fermions they may induce long-range forces that can cause great changes in the neutrino evolution in matter, in particular, in the Sun. Current data from solar neutrino experiments and KamLAND allow us to place stringent limits on those new interactions.
We investigate the potential of a future kilometer-scale neutrino telescope, such as the proposed... more We investigate the potential of a future kilometer-scale neutrino telescope, such as the proposed IceCube detector in the South Pole, to measure and disentangle the yet unknown components of the cosmic neutrino flux, the prompt atmospheric neutrinos coming from the decay of charmed particles and the extra-galactic neutrinos in the 10 TeV to 1 EeV energy range. Assuming a power law type spectra, dφν/dEν˜αEβν, we quantify the discriminating power of the IceCube detector and discuss how well we can determine magnitude (α) as well as slope (β) of these two components of the high energy neutrino spectrum, taking into account the background coming from the conventional atmospheric neutrinos.
We have investigated the possibility of discerning mass from flavor changing neutrino interaction... more We have investigated the possibility of discerning mass from flavor changing neutrino interactions induced $\nu_\mu \to \nu_\tau$ oscillations in the long baseline neutrino experiments K2K and MINOS. We have found that for virtually any value of the flavor conserving parameter $\epsilon^\prime$ it will be possible to, independently, distinguish these two mechanisms at K2K, if the flavor changing parameter $\epsilon$ is in the range $\epsilon \gsim 0.77$, and at MINOS, if $\epsilon \gsim 0.2$. Moreover, if K2K measures a depletion of the expected $\nu_\mu$ flux then MINOS will either observe or discard completely flavor changing neutrino oscillations.
We find an exact analytic solution for the time evolution of a three Dirac neutrino system adiaba... more We find an exact analytic solution for the time evolution of a three Dirac neutrino system adiabatically oscillating in matter, constructing explicitly the relevant $3\times 3$ mixing matrix in matter. Using this result we investigate the solar neutrino data in a scenario where the neutrino masses are such that $m_1\alt m_2\ll m_3$, taking into account several phenomenological constraints on neutrino mixing angles and masses. A solution of the solar neutrino problem for large values of the parameter $\delta m^2=m_2^2-m_1^2$ which are not usually associated with a resonance is found. This is an essentially three-generation effect.
This is a crash course that aims to serve as a guide for students who wish to learn the Monte Car... more This is a crash course that aims to serve as a guide for students who wish to learn the Monte Carlo Simulation Technique and its applications to particle physics. The general ideas about the Monte Carlo Method of Integration is discussed but emphasis is given to the use of Monte Carlo to theoretically predict the value of observables and compare the theoretical prediction with experimental data.
Assuming that neutrinos are Majorana particles, in a three-generation framework, current and futu... more Assuming that neutrinos are Majorana particles, in a three-generation framework, current and future neutrino oscillation experiments can determine six out of the nine parameters which fully describe the structure of the neutrino mass matrix. We try to clarify the interplay among the remaining parameters, the absolute neutrino mass scale and two CP violating Majorana phases, and how they can be accessed by future neutrinoless double beta (0νββ) decay experiments, for the normal as well as for the inverted order of the neutrino mass spectrum. Assuming the oscillation parameters to be in the range presently allowed by atmospheric, solar, reactor, and accelerator neutrino experiments, we quantitatively estimate the bounds on m0, the lightest neutrino mass, that can be inferred if the next generation 0νββ decay experiments can probe the effective Majorana mass (mee) down to ~1 meV. In this context we conclude that in the case that neutrinos are Majorana particles, (a) if m0>~300 meV, i.e., within the range directly attainable by future laboratory experiments as well as astrophysical observations, then mee>~30 meV must be observed, (b) if m0<300 meV, results from future 0νββ decay experiments combined with stringent bounds on the neutrino oscillation parameters, especially the solar ones, will place much stronger limits on the allowed values of m0 than these direct experiments. For instance, if a positive signal is observed around mee=10 meV, we estimate 3<~m0/meV<~65 at 95% C.L.; on the other hand, if no signal is observed down to mee=10 meV, then m0<~55 meV at 95% C.L.
We perform a detailed analysis of the capabilities of the MINOS, ICARUS and OPERA experiments to ... more We perform a detailed analysis of the capabilities of the MINOS, ICARUS and OPERA experiments to measure neutrino oscillation parameters at the atmospheric scale with their data taken separately and in combination. MINOS will determine Δm232 and sin22θ23 to within 10% at the 99% C.L. with 10 kton-years of data. While no one experiment will determine sin22θ13 with much precision, if its value lies in the combined sensitivity region of the three experiments, it will be possible to place a lower bound of O(0.01) at the 95% C.L. on this parameter by combining the data from the three experiments. The same bound can be placed with a combination of MINOS and ICARUS data alone.
Based on the work by N. Cipriano Ribeiro et. al., JHEP 0712, 002 (2007) [arXiv:0709.1980 [hep-ph]... more Based on the work by N. Cipriano Ribeiro et. al., JHEP 0712, 002 (2007) [arXiv:0709.1980 [hep-ph]], in this poster, we discuss the potential of a neutrino factory to probe the so called non-standard neutrino interactions (NSI) with matter, which may exist as a low-energy manifestation of physics beyond the Standard Model. Using the appearance modes νe rangle νμ/erangleμ, we demonstrate how powerful is the setting of two detectors with different baselines, one at L = 3000 km and the other at L = 7000 km, where the latter is nearly at the magic baseline which is known to have a great sensitivity to matter density determination. Assuming the effects of NSI at the production and the detection are negligible, we study the impact of NSI in the neutrino propagation, and determine the sensitivity to NSI parameters, epsilonαβ, and at the same time discuss how the determination of θ13 and δ is affected. We found that the effect of 'synergy' of combing two detectors is significant, providing high sensitivity to NSI parameters and powerful enough to resolve the confusion between θ13 and the NSI effect. We obtain, for example, at sin2 2θ13 = 10-4, the sensitivity of |epsiloneτ| a few x 10-3 at 3σ CL for 2 degrees of freedom, without loosing much the sensitivity to θ13 and δ. Our results imply that neutrino factory can be a hunting machine for NSI while keeping its primary function of performing precision measurements of the lepton mixing parameters.
If the lepton mixing angle θ23 is not maximal, there arises a problem of ambiguity in determining... more If the lepton mixing angle θ23 is not maximal, there arises a problem of ambiguity in determining θ23 due to the existence of two degenerate solutions, one in the first and the other in the second octant. We discuss an experimental strategy for resolving the θ23 octant degeneracy by combining reactor measurement of θ13 with accelerator νμ disappearance and νe appearance experiments. The robustness of the θ23 degeneracy and the difficulty in lifting it only by accelerator experiments with conventional νμ (and ν¯μ) beams are demonstrated by analytical and numerical treatments. Our method offers a way to overcome the difficulty and can resolve the degeneracy between solutions sin2θ23=0.4 and sin2θ23=0.6 if sin22θ13≳0.05 at 95% CL by assuming the T2K phase II experiment and a reactor measurement with an exposure of 10 GW·kt·yr. The dependence of the resolving power of the octant degeneracy on the systematic errors of reactor experiments is also examined.
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