Physics at a Fermilab Proton Driver
This report documents the physics case for building a 2 MW, 8 GeV superconducting linac proton driver at Fermilab.
hep-ex↗
arXiv subjects
O. Mena
Publications and source records attributed to O. Mena.
The Neutrino Factory and Beta Beam Experiments and Development
The long-term prospects for fully exploring three-flavor mixing in the neutrino sector depend upon an ongoing and increased investment in the appropriate accelerator R&D. Two new concepts have been proposed that would revolutionize neutrino experiments, namely the Neutrino Factory and the Beta Beam facility. These new facilities would dramatically improve our ability to test the three-flavor mixing framework, measure \textsl{CP} violation in the lepton sector, and perhaps determine the neutrino mass hierarchy, and, if necessary, probe extremely small values of the mixing angle $θ_{13}$. The stunning sensitivity that could be achieved with a Neutrino Factory is described, together with our present understanding of the corresponding sensitivity that might be achieved with a Beta Beam facility. In the Beta Beam case, additional study is required to better understand the optimum Beta Beam energy, and the achievable sensitivity. Neither a Neutrino Factory nor a Beta Beam facility could be built without significant R&D. An impressive Neutrino Factory R&D effort has been ongoing in the U.S. and elsewhere over the last few years and significant progress has been made towards optimizing the design, developing and testing the required accelerator components, and significantly reducing the cost. The recent progress is described here.
physics.acc-ph↗
Corrections to the fluxes of a Neutrino Factory
In view of their physics goals, future neutrino factories from muon decay aim at an overall flux precision of ${\cal O}(1%)$ or better. We analytically study the QED radiative corrections to the neutrino differential distributions from muon decay. Kinematic uncertainties due to the divergence of the muon beam are considered as well. The resulting corrections to the neutrino flux turn out to be of order ${\cal O}(0.1%)$, safely below the required precision.
hep-ph↗
Puzzling out Neutrino Mixing Through Golden and Silver Measurements
We update a recent work devoted to resolve the degeneracies that appear in the simultaneous extraction of $θ_{13}$ and $δ$ at future Neutrino Factories (NF, that exploit the \emph{golden} channels, i.e. $ν_e\toν_μ$ ($\barν_e\to\barν_μ$)) and Superbeam experiments (SB, that measure the $ν_μ\toν_e$ ($\barν_μ\to\barν_e$) transitions). We consider the neutrino fluxes obtained with a new optics design for the CERN-SPL SB and assume the solar parameters within the LMA-I and the LMA-II regions indicated by recent KamLAND data. The dangerous fake solution associated with the $θ_{23}$-ambiguity remains after the combination of data from these two facilities: in this perspective, we analyze the impact of the NF-\emph{silver} channels, i.e. $ν_e\toν_τ$ ($\barν_e\to\barν_τ$). The combination of data from these three experiments -NF(\emph{golden} and \emph{silver} channels) plus SPL SB- can discover leptonic CP violation for values of $θ_{13}\ge 1^{\circ}$.
hep-ph↗
Superbeams plus Neutrino Factory: the golden path to leptonic CP violation
Superbeams (SB) and Neutrino Factories (NF) are not alternative facilities for exploring neutrino oscillation physics, but successive steps. The correct strategy is to contemplate the combination of their expected physics results. We show its important potential on the disappearance of fake degenerate solutions in the simultaneous measurement of $θ_{13}$ and leptonic CP violation. Intrinsic, sign($Δm_{13}^2$) and $θ_{23}$ degeneracies are shown to be extensively eliminated when the results from one NF baseline and a SB facility are combined. A key point is the different average neutrino energy and baseline of the facilities. For values of $θ_{13}$ near its present limit, the short NF baseline, e.g. L=732 km,becomes, after such a combination, a very interesting distance. For smaller $θ_{13}$, an intermediate NF baseline of $O(3000$km) is still required.
hep-ph↗
Leptonic CP Violation at the neutrino factory
In this talk, based on the work \cite{cpviolation}, we refine our previous analysis \cite{golden} of the sensitivity to leptonic CP violation and $\tetaot$ at a neutrino factory in the LMA-MSW scenario, by exploring the full range of these two parameters. We have discovered that there exist, at fixed neutrino energy, $E_ν$, and baseline, $L$, degenerate solutions. Although the spectral analysis helps in disentangling fake from true solutions, a leftover product of this degeneracy remains for a realistic detector, which we analyse. Furthermore, we take into account the expected uncertainties on the solar and atmospheric oscillation parameters and in the average Earth matter density along the neutrino path. An intermediate baseline of O(3000) km is still the best option to tackle CP violation, although a combination of two baselines turns out to be very important in resolving degeneracies. This summary is based on a talk given at NUFACT01, May 2001, Tsukuba (Japan).
hep-ph↗
On the measurement of leptonic CP violation
We show that the simultaneous determination of the leptonic CP-odd phase $δ$ and the angle $θ_{13}$ from the subleading transitions $ν_e\toν_μ$ and ${\barν}_e\to{\barν}_μ$ results generically, at fixed neutrino energy and baseline, in two degenerate solutions. In light of this, we refine a previous analysis of the sensitivity to leptonic CP violation at a neutrino factory, in the LMA-MSW scenario, by exploring the full range of $δ$ and $θ_{13}$. Furthermore, we take into account the expected uncertainties on the solar and atmospheric oscillation parameters and in the average Earth matter density along the neutrino path. An intermediate baseline of O(3000) km is still the best option to tackle CP violation, although a combination of two baselines turns out to be very important in resolving degeneracies.
hep-ph↗
Golden measurements at a neutrino factory
The precision and discovery potential of a neutrino factory based on muon storage rings is studied. For three-family neutrino oscillations, we analyse how to measure or severely constraint the angle $θ_{13}$, CP violation, MSW effects and the sign of the atmospheric mass difference $Δm^2_{23}$. We present a simple analytical formula for the oscillation probabilities in matter, with all neutrino mass differences non-vanishing, which clarifies the subtleties involved in disentangling the unknown parameters. The appearance of ``wrong-sign muons'' at three reference baselines is considered: 732 km, 3500 km, and 7332 km. We exploit the dependence of the signal on the neutrino energy, and include as well realistic background estimations and detection efficiencies. The optimal baseline turns out to be ${\cal O}(3000$ km). Analyses combining the information from different baselines are also presented.
hep-ph↗
Summary of Golden Measurements at a $ν$-Factory
The precision and discovery potential of a neutrino factory based on muon storage rings is summarized. For three-family neutrino oscillations, we analyze how to measure or severely constraint the angle $θ_{13}$, CP violation, MSW effects and the sign of the atmospheric mass difference $Δm^2_{23}$. The appearance of ``wrong-sign muons'' at three reference baselines is considered: 732 km, 3500 km and 7332 km. We exploit the dependence of the signal on the neutrino energy, and include as well realistic background estimations and detection efficiencies. The optimal baseline turns out to be $O$(3000 km).
hep-ph↗