arXiv subjects

Pilar Coloma

Publications and source records attributed to Pilar Coloma.

61 records · Page 4Linked to original sources

arXiv2012

Optimization of neutrino oscillation facilities for large θ_{13}

Up to now, future neutrino beam experiments have been designed and optimized in order to look for CP violation, θ_{13} and the mass hierarchy under the conservative assumption that θ_{13} is very small. However, the recent results from T2K and MINOS favor a θ_{13} which could be as large as 8^{\circ}. In this work, we propose a re-optimization for neutrino beam experiments in case this hint is confirmed. By switching from the first to the second oscillation peak, we find that the CP discovery potential of future oscillation experiments would not only be enhanced, but it would also be less affected by systematic uncertainties. In order to illustrate the effect, we present our results for a Super-Beam experiment, comparing the results obtained at the first and the second oscillation peaks for several values of the systematic errors. We also study its combination with a β-beam facility and show that the synergy between both experiments would also be enhanced due to the larger L/E. Moreover, the increased matter effects at the larger L/E also significantly improves the sensitivity to the mass hierarchy.

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arXiv2011

Long baseline Super-Beam experiments in Europe within LAGUNA

We explore the physics reach of several possible configurations for a Super-Beam experiment in Europe, focusing on the possibilities of discovering $θ_{13}$, CP violation in the leptonic sector and the ordering of neutrino mass eigenstates. We consider the three different detector technologies: Water Čerenkov, Liquid Argon and Liquid Scintillator, and seven possible sites in Europe which would be able to host such a detector underground. The distances to these sites from CERN, where the beam would be originated, go from 130 km to 2300 km. The neutrino flux is optimized in each case as to match the first oscillation peak for each of the baselines under consideration. We also study the impact of several experimental factors in the performance of each detector technology. These include the influence of the spectral information, the rejection efficiencies for the neutral-current backgrounds, the ratio between running times in neutrino and antineutrino modes and the systematic uncertainties on the signal and backgrounds, among others.

hep-ph↗

arXiv2011

Heavy Neutrinos and Lepton Number Violation in lp Colliders

We discuss the prospects of studying lepton number violating processes in order to identify Majorana neutrinos from low scale seesaw mechanisms at lepton-proton colliders. In particular, we consider the scenarios of colliding electrons with LHC energy protons and, motivated by the efforts towards the construction of a muon collider, the prospects of muon-proton collisions. We find that present constraints on the mixing of the Majorana neutrinos still allow for a detectable signal at these kind of facilities given the smallness of the Standard Model background. We discuss possible cuts in order to further increase the signal over background ratio and the prospects of reconstructing the neutrino mass from the kinematics of the final state particles.

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arXiv2010

Summary report of MINSIS workshop in Madrid

Recent developments on tau detection technologies and the construction of high intensity neutrino beams open the possibility of a high precision search for non-standard μ - τ flavour transition with neutrinos at short distances. The MINSIS - Main Injector Non-Standard Interaction Search- is a proposal under discussion to realize such precision measurement. This document contains the proceedings of the workshop which took place on 10-11 December 2009 in Madrid to discuss both the physics reach as well as the experimental requirements for this proposal.

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arXiv2009

Optimized Two-Baseline Beta-Beam Experiment

We propose a realistic Beta-Beam experiment with four source ions and two baselines for the best possible sensitivity to theta_{13}, CP violation and mass hierarchy. Neutrinos from 18Ne and 6He with Lorentz boost gamma=350 are detected in a 500 kton water Cerenkov detector at a distance L=650 km (first oscillation peak) from the source. Neutrinos from 8B and 8Li are detected in a 50 kton magnetized iron detector at a distance L=7000 km (magic baseline) from the source. Since the decay ring requires a tilt angle of 34.5 degrees to send the beam to the magic baseline, the far end of the ring has a maximum depth of d=2132 m for magnetic field strength of 8.3 T, if one demands that the fraction of ions that decay along the straight sections of the racetrack geometry decay ring (called livetime) is 0.3. We alleviate this problem by proposing to trade reduction of the livetime of the decay ring with the increase in the boost factor of the ions, such that the number of events at the detector remains almost the same. This allows to substantially reduce the maximum depth of the decay ring at the far end, without significantly compromising the sensitivity of the experiment to the oscillation parameters. We take 8B and 8Li with gamma=390 and 656 respectively, as these are the largest possible boost factors possible with the envisaged upgrades of the SPS at CERN. This allows us to reduce d of the decay ring by a factor of 1.7 for 8.3 T magnetic field. Increase of magnetic field to 15 T would further reduce d to 738 m only. We study the sensitivity reach of this two baseline two storage ring Beta-Beam experiment, and compare it with the corresponding reach of the other proposed facilities.

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arXiv2009

Optimization of the Two-Baseline Beta-Beam

We propose a $β$-Beam experiment with four source ions and two baselines for the best possible sensitivity to $θ_{13}$, CP violation and mass hierarchy. Neutrinos from $^{18}$Ne and $^6$He with Lorentz boost $γ=350$ are detected in a 500 kton water \chr detector at a distance L=650 km from the source. Neutrinos from $^8$B and $^8$Li are detected in a 50 kton magnetized iron detector at a distance L=7000 km from the source. Since a tilt angle $\vartheta=34.5^\circ$ is required to send the beam to the magic baseline, the far end of the ring has a maximum depth of $d=2132$ m. We alleviate this problem by proposing to trade reduction of the decay ring with the increase in the boost factor of the $^8$Li and $^8$B ions up to $γ_{^8\mathrm{Li}}=390$ and $γ_{^8\mathrm{Li}}=650$, such that the number of events at the detector remains almost the same. We study the sensitivity reach of this two-baseline two-storage ring $β$-Beam experiment, and compare it with the corresponding reach of the other proposed facilities.

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arXiv2008

$θ_{13}$, $δ$ and the neutrino mass hierarchy at a $γ=350$ double baseline Li/B $β$-Beam

We consider a $β$-Beam facility where $^8$Li and $^8$B ions are accelerated at $γ= 350$, accumulated in a 10 Km storage ring and let decay, so as to produce intense $\bar ν_e$ and $ν_e$ beams. These beams illuminate two iron detectors located at $L \simeq 2000$ Km and $L \simeq 7000$ Km, respectively. The physics potential of this setup is analysed in full detail as a function of the flux. We find that, for the highest flux ($10 \times 10^{18}$ ion decays per year per baseline), the sensitivity to $θ_{13}$ reaches $\sin^2 2 θ_{13} \geq 2 \times10^{-4}$; the sign of the atmospheric mass difference can be identified, regardless of the true hierarchy, for $\sin^2 2 θ_{13} \geq 4\times10^{-4}$; and, CP-violation can be discovered in 70% of the $δ$-parameter space for $\sin^2 2 θ_{13} \geq 10^{-3}$, having some sensitivity to CP-violation down to $\sin^2 2 θ_{13} \geq 10^{-4}$ for $|δ| \sim 90^\circ$.

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