Final Report Summary - T2KQMUL (Study of Neutrino Oscillations at T2K)
Understanding the nature of neutrinos and their role in the Universe answers questions beyond the current frontier of our knowledge.
The T2KQMUL group worked on neutrino physics giving vital contributions to it understanding and answering open questions in physics. Its improved understanding is shaping the current plan of the future neutrino experiments.
In more detail, the main achievement of this project is the original contribution to the electron nutrino appearance within the T2K experiment that paves the way to the measurement of the charge-parity (CP) violation in the leptonic sector, and answers a major open question in physics we had a few years ago. CP violation can then explain the matter-antimatter asymmetry in the current Universe, ie why in the current Universe the matter dominates.
During the past few decades, particle physics has made unprecedented progress in understanding the laws of nature at the most fundamental level. Based on this understanding, a framework, the Standard Model of Particle Physics, capable of describing the whole variety of observed particles and interactions in terms of a few fundamental interactions and elementary particles, has been developed since about 1960.
However, the first and most striking evidence of a shortcoming of the Standard Model comes from neutrinos. The experimental picture developed in the last ten years is consistent with three neutrino families undergoing oscillations, i.e. neutrinos created with a specific lepton flavour can later be measured to have a different flavour, which can only happen if neutrinos have masses and mix.
A main missing ingredient for understanding neutrino oscillations was the measurement of neutrinos of one flavour appearing from another flavour – before only the disappearance of neutrinos was observed. The T2KQMUL group gave a vital contribution to the understanding of the neutrino spectrum, for a final measurement of the muon-into-electron neutrino appearance. This work resulted in several papers, and in particular the paper on the first indication of electron neutrino appearance in 2011 collected so far about 1000 citations, which is quite remarkable for a so recent paper. The group concentrated on developing a new original approach to the measurement of the data before oscillation to achieve a very high precision to then claim an observation.
The impact of this observation is the shaping of the future experiments. Those are mainly designed to measure CP violation, and the determination of the appearance gives stringent criteria of the main design of the experiments.
Two further main analyses are performed by the group, one concentrating on the reduction of the total error envelop on the observation of the electron neutrino appearance through a first measurement at T2K of the neutrino cross section on water, where the neutrino cross section can be considered the probability of neutrino interaction with matter, and the other setting limits on physics beyond the Standard Model, where both limits on sterile neutrinos, i.e. neutrinos that do not interact with the matter, and on Lorentz Violation in neutrino oscillations are set.
Finally, taking into account the above results a study on the sensitivity on future long baseline neutrino experiments has been performed and published helping to shape the design of the future experiments.
In conclusion, this grant has been extremely successful, with major papers published, and shaping the way to new future experiments. All the objectives of the project were fully met and some of them overachieved.
The T2KQMUL group worked on neutrino physics giving vital contributions to it understanding and answering open questions in physics. Its improved understanding is shaping the current plan of the future neutrino experiments.
In more detail, the main achievement of this project is the original contribution to the electron nutrino appearance within the T2K experiment that paves the way to the measurement of the charge-parity (CP) violation in the leptonic sector, and answers a major open question in physics we had a few years ago. CP violation can then explain the matter-antimatter asymmetry in the current Universe, ie why in the current Universe the matter dominates.
During the past few decades, particle physics has made unprecedented progress in understanding the laws of nature at the most fundamental level. Based on this understanding, a framework, the Standard Model of Particle Physics, capable of describing the whole variety of observed particles and interactions in terms of a few fundamental interactions and elementary particles, has been developed since about 1960.
However, the first and most striking evidence of a shortcoming of the Standard Model comes from neutrinos. The experimental picture developed in the last ten years is consistent with three neutrino families undergoing oscillations, i.e. neutrinos created with a specific lepton flavour can later be measured to have a different flavour, which can only happen if neutrinos have masses and mix.
A main missing ingredient for understanding neutrino oscillations was the measurement of neutrinos of one flavour appearing from another flavour – before only the disappearance of neutrinos was observed. The T2KQMUL group gave a vital contribution to the understanding of the neutrino spectrum, for a final measurement of the muon-into-electron neutrino appearance. This work resulted in several papers, and in particular the paper on the first indication of electron neutrino appearance in 2011 collected so far about 1000 citations, which is quite remarkable for a so recent paper. The group concentrated on developing a new original approach to the measurement of the data before oscillation to achieve a very high precision to then claim an observation.
The impact of this observation is the shaping of the future experiments. Those are mainly designed to measure CP violation, and the determination of the appearance gives stringent criteria of the main design of the experiments.
Two further main analyses are performed by the group, one concentrating on the reduction of the total error envelop on the observation of the electron neutrino appearance through a first measurement at T2K of the neutrino cross section on water, where the neutrino cross section can be considered the probability of neutrino interaction with matter, and the other setting limits on physics beyond the Standard Model, where both limits on sterile neutrinos, i.e. neutrinos that do not interact with the matter, and on Lorentz Violation in neutrino oscillations are set.
Finally, taking into account the above results a study on the sensitivity on future long baseline neutrino experiments has been performed and published helping to shape the design of the future experiments.
In conclusion, this grant has been extremely successful, with major papers published, and shaping the way to new future experiments. All the objectives of the project were fully met and some of them overachieved.