In Defence of Future Generations: A Reply to Stephen Humphreys

In this reply to Stephen Humphreys, we challenge the dismissal of future generations as a locus of responsibility for present generations. Drawing from diverse sources such as indigenous law, environmental jurisprudence and practice, we demonstrate that global discourse on intergenerationality is broader and more nuanced than Humphreys suggests. Our response highlights the importance of incorporating diverse perspectives to enrich discourse and promote an inclusive approach to the progressive development of international law. Further, we contend that ‘future generations’ discourse has emancipatory power, offering potential for reshaping international law based on a vision of justice and solidarity across time and space. We call for increased dialogue and collaboration among scholars, practitioners and frontline communities to ensure that future generations discourse remains grounded in real-world experiences. By persistently interrogating and developing our understanding of responsibilities owed to future generations, we can imagine and cultivate a more inclusive – and, hence, more promising – approach to addressing climate change and related global crises

Neutrino parameters from matter effects in PeeP_{ee} at long baselines

We show that the earth matter effects in the ${\rm {\nu_e \to \nu_e}}$ survival probability can be used to cleanly determine the third leptonic mixing angle $\theta_{13}$ and the sign of the atmospheric neutrino mass squared difference, $\Delta m^2_{31}$, using a $\beta$-beam as a $\nu_e$ source.Comment: 4 pages, 4 eps figures; comments and references added, to appear in Phys. Rev.

Precision on leptonic mixing parameters at future neutrino oscillation experiments

We perform a comparison of the different future neutrino oscillation experiments based on the achievable precision in the determination of the fundamental parameters theta_{13} and the CP phase, delta, assuming that theta_{13} is in the range indicated by the recent Daya Bay measurement. We study the non-trivial dependence of the error on delta on its true value. When matter effects are small, the largest error is found at the points where CP violation is maximal, and the smallest at the CP conserving points. The situation is different when matter effects are sizable. As a result of this effect, the comparison of the physics reach of different experiments on the basis of the CP discovery potential, as usually done, can be misleading. We have compared various proposed super-beam, beta-beam and neutrino factory setups on the basis of the relative precision of theta_{13} and the error on delta. Neutrino factories, both high-energy or low-energy, outperform alternative beam technologies. An ultimate precision on theta_{13} below 3% and an error on delta of < 7^{\circ} at 1 sigma (1 d.o.f.) can be obtained at a neutrino factory.Comment: Minor changes, matches version accepted in JHEP. 30 pages, 9 figure

A minimal Beta Beam with high-Q ions to address CP violation in the leptonic sector

In this paper we consider a Beta Beam setup that tries to leverage at most existing European facilities: i.e. a setup that takes advantage of facilities at CERN to boost high-Q ions (8Li and 8B) aiming at a far detector located at L = 732 Km in the Gran Sasso Underground Laboratory. The average neutrino energy for 8Li and 8B ions boosted at \gamma ~ 100 is in the range E_\nu = [1,2] GeV, high enough to use a large iron detector of the MINOS type at the far site. We perform, then, a study of the neutrino and antineutrino fluxes needed to measure a CP-violating phase delta in a significant part of the parameter space. In particular, for theta_13 > 3 deg, if an antineutrino flux of 3 10^19 useful 8Li decays per year is achievable, we find that delta can be measured in 60% of the parameter space with 6 10^18 useful 8B decays per year.Comment: 19 pages, 10 figures, added references and corrected typo

Neutrino Mixings and Leptonic CP Violation from CKM Matrix and Majorana Phases

The high scale mixing unification hypothesis recently proposed by three of us (R. N. M., M. K. P. and G. R.) states that if at the seesaw scale, the quark and lepton mixing matrices are equal then for quasi-degenerate neutrinos, radiative corrections can lead to large solar and atmospheric mixings and small reactor angle at the weak scale in agreement with data. Evidence for quasi-degenerate neutrinos could, within this framework, be interpreted as a sign of quark-lepton unification at high scale. In the current work, we extend this model to show that the hypothesis works quite successfully in the presence of CP violating phases (which were set to zero in the first paper). In the case where the PMNS matrix is identical to the CKM matrix at the seesaw scale, with a Dirac phase but no Majorana phase, the low energy Dirac phase is predicted to be ($\simeq 0.3^{\circ}$) and leptonic CP-violation parameter $J_{CP} \simeq (4 - 8)\times 10^{-5}$ and $\theta_{13} = 3.5^{\circ}$. If on the other hand, the PMNS matrix is assumed to also have Majorana phases initially, the resulting theory damps radiative magnification phenomenon for a large range of parameters but nevertheless has enough parameter space to give the two necessary large neutrino mixing angles. In this case, one has $\theta_{13} = 3.5^{\circ} - 10^{\circ}$ and $|J_{CP}|$ as large as $0.02-0.04$ which are accessible to long baseline neutrino oscillation experiments.Comment: 15 pages and 10 figures, typo correcte

Probing the Neutrino Mass Hierarchy with Super-Kamiokande

We show that for recently discovered large values of theta(13), a superbeam with an average neutrino energy of ~ 5 GeV, such as those being proposed at CERN, if pointing to Super-Kamiokande (L = 8770 km), could reveal the neutrino mass hierarchy at 5 sigma in less than two years irrespective of the true hierarchy and CP phase. The measurement relies on the near resonant matter effect in the numu to nue oscillation channel, and can be done counting the total number of appearance events with just a neutrino beam.Comment: 16 pages, 7 pdf figures, 2 tables. Format changed and text extended. Four new pdf figures added. Dependency of the result on 1-3 mixing angle discussed. Conclusions unchanged. Accepted in JHE

Potential of optimized NOvA for large theta(13) & combined performance with a LArTPC & T2K

NOvA experiment has reoptimized its event selection criteria in light of the recently measured moderately large value of theta(13). We study the improvement in the sensitivity to the neutrino mass hierarchy and to leptonic CP violation due to these new features. For favourable values of deltacp, NOvA sensitivity to mass hierarchy and leptonic CP violation is increased by 20%. Addition of 5 years of neutrino data from T2K to NOvA more than doubles the range of deltacp for which the leptonic CP violation can be discovered, compared to stand alone NOvA. But for unfavourable values of deltacp, the combination of NOvA and T2K are not enough to provide even a 90% C.L. hint of hierarchy discovery. Therefore, we further explore the improvement in the hierarchy and CP violation sensitivities due to the addition of a 10 kt liquid argon detector placed close to NOvA site. The capabilities of such a detector are equivalent to those of NOvA in all respects. We find that combined data from 10 kt liquid argon detector (3 years of nu + 3 years of nubar run), NOvA (6 years of nu + 6 years of nubar run) and T2K (5 years of nu run) can give a close to 2 sigma hint of hierarchy discovery for all values of deltacp. With this combined data, we can achieve CP violation discovery at 95% C.L. for roughly 60% values of deltacp.Comment: 22 pages, 24 pdf figures, 5 tables. In the appendix, new results are presented with conservative choices of central values of oscillation parameters. New references are added. Accepted in JHE

MiniBooNE Oscillation Results 2011

The MiniBooNE neutrino oscillation search experiment at Fermilab has recently updated results from a search for $\bar\nu_\mu \rightarrow \bar\nu_e$ oscillations, using a data sample corresponding to $8.58 \times 10^{20}$ protons on target in anti-neutrino mode. This high statistics result represent an increase in statistics of 52% compared to result published in 2010. An excess of 57.7 $\pm$ 28.5 events is observed in the energy range 200 MeV $< E_\nu <$ 3000 MeV. The data favor LSND-like $\bar\nu_\mu \rightarrow \bar\nu_e$ oscillations over a background only hypothesis at 91.1% confidence level in the energy range 475 $< E_\nu<$3000 MeV.Comment: 4 pages, 6 figures, talk given at NuFact 2011, XIIIth InternationalWorkshop on Neutrino Factories, Super beams and Beta beams, CERN/UNIGE, Geneva, Switzerland, August 1-6, 201