PoS(NOW2016)076 http://pos.sissa.it/ [email protected] [email protected] This paper summarizes the parallel sessionsession covered IV: experimental "Neutrino and theoretical masses, aspects states of and thefor absolute interactions". neutrinoless neutrino mass double This scale, beta searches decay,Beyond and that, searches lepton for flavor violation sterile in the neutrinos chargeddecay, in lepton and sector, different electromagnetic exotic mass properties interactions of in regimes. tritium neutrinos beta were discussed. Copyright owned by the author(s) under the terms of the Creative Commons c Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). Neutrino Oscillation Workshop 4 - 11 September, 2016 Otranto (Lecce, Italy) Stefano Morisi INFN, Sezione di Napoli, Complesso Univ.Dipartimento Monte di S. Fisica Angelo, Ettore I-80126 Pancini, Universita Napoli,E-mail: di Italy Napoli Federico II Susanne Mertens Max Planck Institute for Physics, FoehringerTechnical Ring University 6, Munich, 80805 James Munich, Frank Str., Germany 85748E-mail: Garching, Germany Neutrino masses, states and interactions PoS(NOW2016)076 ], 4 (2.1) ]. 7 ] 1 ˜ H j ˜ HL i ] and even at three loops [ L 6 1 , ν i j Λ y 5 ⊃ is an arbitrary matrix. Such an operator gives rise to a ν i j L y ] for a review). But the Weinberg operator can be realized at 3 ]) depending if the mediator is a fermion SU(2) singlet, scalar SU(2) triplet or 2 is an effective mass scale and Λ All these extensions of the standard model are possible realizations of the Weinberg opera- The origin and the nature of neutrino is still a mystery and is one of the biggest question in In the parallel session "Neutrino masses, states and interactions" eight experimental and five In the standard model neutrinos are massless at the renormalizable level, but neutrinos get the renormalizable level also radiatively by means of one-loop diagrams like the Zee model [ two-loop Feynman diagram Zee-Babu model [ fermion SU(2) triplet, respectively. The mediators canhigh-mass have scales very different are mass scales quite butcounterexample typically natural where the for right-handed such neutrino can kindI be of seesaw just mechanism above mechanisms. but the the electroweak Dirac scale Lopez-Pavonnon-unitarity Yukawa in couplings has effects a have type- not presented that to can a be be smallthere giving tested is rise in to a lepton interesting class flavornaturally violation of experiments. low, mechanisms around (inverse On TeV and the (see other linear [ hand seesaw) where the new physics scale can be Majorana mass for neutrinos. However we doand not so know if we neutrinos do are not Dirac knowunderstand or the Majorana if renormalizable particles such theory that an is effective hidden operatorlevel in is the there Weinberg present operator. are or At many the not. possibilities renormalizable at Ifscenarios three present, we it level can as is well have important as to low new from scale. physics radiative At at contributions tree and high level in(see scale we both for (of can instance have the [ the order standard of seesaw the mechanisms denoted grand as unified type-I, scale) II or or at III tor and give rise toparticles we a have Majorana to mass extend the forjorana/Dirac Standard neutrino. Model makes including a On the big right-handed the neutrino difference other fields. from hand So the Ma- if theoretical neutrino point are of pure view Dirac In such a case it is quite where physics, theoretically and experimentally. In both contextsget it mass is and fundamental if to neutrinos know are how Majorananature neutrinos or are Dirac intimately particles. related The and neutrino anyture mass experimental will mechanisms progress improve and definitively on their also the the determination knowledgehand on about the neutrino’s knowing na- neutrino the mass nature mechanism. of OnIn neutrinos the other will order not to fix better completely understandinteractions. the problem This this is of important the the properties reason mass of it generation. the is title required of this to IV learntheoretical parallel talks also section. were about presented. neutrino The experimentalsearches, talks direct comprised neutrino neutrinoless double mass beta measurements,was decay and composed of searches two for talks sterile onon neutrinos. the the nature origin The on of theory neutrino. neutrino part mass, two talks on their interactions2. and one Theory mass by means of the Weinberg non-renormalizable operator [ Neutrino masses, states and interactions 1. Introduction PoS(NOW2016)076 ]). the 8 i m element of ee half-life it is cru- νββ . It has been showed that 2. It is alo true the opposite, = L is the quark Cabibbo angle (that is the permutation of four objects, and ∆ C 4 θ S is the neutrino mixing matrix and U half-life time is proportional to the parameter 2 νββ where | i m ie "(not only) neutrino and GUTs" ]. In particular the case of keV-scale sterile neutrinos and U 9 i ∑ | = | ee ) ν is the lepton mixing angle and m ( | 12 θ will be observed then neutrino are Majorana particles (black box theorem [ ]. 4 where 10 / π νββ is proportional to a parameter related to the neutrino physics, that is the ≈ . On the other hand in order to extract such a parameter from 0 | C ) with a violation of the lepton number of two units θ νββ ee ) An example of neutrino interaction has be discussed by Studenikin that in particular has given The experimental part of the session covered lepton number violaton in the charged lepton On the top of such a complicated puzzle, there is another problem that is deeply connected As the KATRIN experiment will soon start data taking, it is interesting to investigate non- + ν νββ m 12 ( a report on the status of the electromagnetic interaction of neutrino. 3. Experiments sector with the MEG experiment, neutrinoideas mass for measurements laboratory with searches the for KATRIN experiment, keV-scale new neutrinoless sterile neutrinos, double a beta variety decay, and of finally experimentsthe searching the relevant for NUMEN nuclear experiment, matrix which elements is for aiming neutrinoless to double determine beta decay. starting form a flavor symmetryθ in GUT it yields aalmost quark-lepton true experimentally). complementary mixing The relation, familythe symmetry grand used unified is group considered are SU(5) and SO(10). with the fermion masses generation:are the mixed flavor problem. as We well knowand that as lepton quarks neutrinos. sectors. of different Moreover On flavors fermionmagnitude. the masses It show other a could hand extremely be wide the thatsymmetry. range There such mixings are that a are in span patterns first very 12 hide approximation orderModel three different some classes of with dynamical in of mechanism gauge possibilities, the by or vertical quark extending some symmetry, thehorizontal underlying like Standard families in symmetries, or the combination casecase of of of vertical the Grand and talk Unified presented horizontal by symmetries. Theories D. (GUT) Meloni This on is or the with right-handed currents was discussd. Interestingly,signatures keV-sterile in neutrino the models beta can decay lead spectrum,sure to while bounds sizable [ not being in contradiction to X-ray limits or overclo- Neutrino masses, states and interactions difficult to explain the suppressionfermions. of Unfortunately the we neutrino havebut no masses if way compared neutrino to have to Majorana prove nature, the experimentally then(0 other if they predict charged neutrino the are Dirac so Dirac called neutrinoless particles, namely double if beta decay 0 The 0 the neutrino mass matrix physical mass neutrino masses. The measured 0 standard decay modes oftargets tritium. a measurement Especially, of with theanywhere the entire tritium in possible spectrum, the realization exotic spectrum of interactionscurrent leading TRISTAN, can interactions which to be in a tritium investigated. deformation betagated decay" In in all an the possible effective operator talk Lorentz-invariant approach interactions by [ were Patrick investi- Ludl on "Exotic charged | cial the precise determination of theexperimental nuclear and matrix theoretical elements. task and This has is been an summarized important by and Simkovic. complicate PoS(NOW2016)076 , s m − 0 E ]. MEG-II = 11 E [ is a coincidence 13 − γ 10 ]. The design sensi- + · + 12 2 e . 4 decay on the stable target → . KATRIN is combining a < β 0 + ) E γ µ muons/s at low momentum of 8 + + e → + µ ( -decay spectrum, at an energy ] β B Right-handed (and hence sterile) neutrinos are 15 decay. A non-zero neutrino mass reduces the , decaying, and hence the mass of the keV-scale 3 β 14 β . In the context of the TRISTAN project of KATRIN Θ 2 The KATRIN experiment is designed to directly measure the ef- Dy is "almost" 137 . e decay and distorts the spectral shape close to The Mu-to-E-Gamma (MEG) experiment searches for charged lepton number + ]. β 13 Ho 137 of the → 0 s is the mass of the new neutrino eigenstate. The amplitude of the signature is determined E -decay spectrum (not only the endpoint region) with a precision in the ppm-level. A ν s β m + Another way to search for dark matter keV-scale sterile neutrinos is via their direct detection. Beyond measuring the neutrino mass, KATRIN –equipped with a new focal plane detector– Since 2016 all components of the KATRIN experiment, including rear-wall, tritium source, The MEG experiment uses an intense DC muon beam of 10 With the full data set accumulated from 2009 to 2013, the MEG collaboration published the Dy Here, a completely new idea was presented, which exploits the inverse has the capability to searchstates would for leave keV-scale a sterile kink-like signature neutrinos. in the New tritium keV-scale neutrino mass eigen- a novel detector and read-outtritium system is being developedmulti-pixel Si-drift that detector would design allow is foreseen to [ measure the entire transport and pumping section, spectrometers, andInstitute focal plane of detector, Technology, are Germany. on-site As at announced thelight" in Karlsruhe of the KATRIN, was presentation, achieved a in majorwere October milestone, transmitted 2016: the through "first electrons, the created 70-m-long atstrates setup the the and functionality rear reached of wall the the of focal magnet KATRIN, measurements system plane are and planned detector. good for This alignment end demon- of of all 2017. components. First tritium Laboratory searches for keV sterile neutrinos by the active-sterile-mixing amplitude sin tivity is 200 meV at 90% CL after three years of measurement time. a natural extension ofeigenstate, the however, Standard is Model. completelymatter unknown. The candidate [ scale keV-scale of sterile the neutrinos corresponding are new motivated neutrino as mass dark where 137 Neutrino masses, states and interactions MEG Experiment is designed to improve the sensitivity by one order of magnitude by 2020. The KATRIN Experiment fective electron anti neutrino mass via tritium violation (cLFV) with muons.naturally Lepton violated number in is Physics conserved beyondallow in to the reveal the SM. or Standard constrain Hence, new Model searches physics (SM), contributions. for but rare is or SM-forbidden decays, world’s leading upper limit of the branching ratio of 29 MeV/c, provided by the piE5signal beam of line the at PSI. back-to-back The emittedlator signature positron measures of the and gamma mono-energetic energy gamma.positrons. and a A drift liquid chamber xenon in scintil- a magnetic field records the track of the endpoint high-luminous gaseous molecular tritium source witha a MAC-E high-resolution filter spectrometer, (Magnetic operating Adiabatic as Collimation with Electrostatic filter) [ PoS(NOW2016)076 y K in ββ 25 42 Q 10 · νββ 5 ≈ c/keV/kg/y 2 2 / 2039 keV and − 1 T , but no particle Te was accumu- = ββ ]. In 2016, the full 130 ββ Q ]. In GERDA Phase- Q . The BEGe detectors 17 2458 keV and an iso- yr · 18 ββ = Q yr for enriched coax was · ββ Q Xe with a high pressure Xenon 137 y was achieved [ 4 keV FWHM at 25 Ge has an endpoint of ]. -decay in − 10 76 c/keV/kg/y and a sensitivity of 16 · 4 1 . − νββ 4 Ge. 2 CUORE is an experiment to search for 0 10 76 Xe has an endpoint of · > 2 in 137 / 1 T y at the 90% CL after 5 years of data taking. 2528 keV and high natural abundance of 34.2%. CUORE νββ 25 y (combined with Cuoricino) was set [ = yr for enriched BEGe and 5.0 kg · 10 24 ββ · 5 Q 10 . · 0 . yr a limit of 4 · > crystals. An excellent energy resolution of 5 keV at 2 / 2 1 T TeO nat bar. Both systems could achieve an energy resolution of 0.5 - 0.6% FWHM at Ge. The detector array is immersed in liquid argon (LAr) as cooling and active veto. GERDA is searching for 0 76 15 Te has an endpoint of NEXT is an experiment to search for 0 − 130 With CUORE-0, a single tower of 52 detectors, an exposure of 9.8 kg In GERDA Phase-1 17.7 kg of coaxial detectors and 5 BEGe detectors were installed. With Two prototypes, called NEXT-DEMO and NEXT-DBDM, were operated at IFIC, Valencia, The next stage, NEXT-WHITE, scheduled from 2016 to 2019 is designed to measure the half- Beyond CUORE several upgrade options are discussed in the context of CUPID. These entail Te. at 90% CL is expected. The CUORE and CUORE-0 experiments identification can be achieved. lated and a limit of a total exposure of 21.6 kg 130 is using a bolometricincrease techniques of where the the energy of the electrons is detected by a temperature a natural abundance of 7.6%.to 86% GERDA in is using bare, high-purity germanium detectors enriched allow for an efficient background discrimination based on the signal pulse shape. II 30 additional BEGe’sAdditionally, were the added individual to detector thefrom strings detector reaching were array the surrounded and detectors. the by Thedata LAr a commissioning release was nylon was an used completed shroud in exposure as to December active of prevent 2015. veto. 5.8 For kg the first GERDA is operating so-called Coaxial (coax) detectorstectors, and providing Broad an Energy excellent Germanium energy (BEGe) resolution de- of 3 Spain and Lawrence Berkeley National LaboratoryXe (LBNL). at They 10 contained about 1 kg of natural life of the two neutrino mode andat to test the the Laboratorio background model. Subterraneo Thesubsequent de detector NEXT-100 is a Canfranc fully background commissioned rate (LSC) of and 4 first data is expected in 2017. With the topic abundance of 8.9%.nal, The detected electrons by emitted TMPs, in and an theSiPMs. ionization decay (amplified The produce via latter a electroluminescence) signal prompt signal,event allows measured scintillation topology to by and sig- reconstruct hence discriminate the signal electron from track, background. which is essential to assess the and demonstrated the characteristic event topology. CUORE detector, consisting of 19 towers wasand completed. the The expected background sensitivity goal is is 9 10 enrichment of the tellurium, an extensionthe of usage the of detector a technology different to isotope. allow for a particleGERDA ID, and NEXT Neutrino masses, states and interactions sterile neutrino is sufficient to makedifferent the measurement inverse modes beta have decay been possible. proposed First [ background studies, and (HPXe) Time Projection Chamber (TPC). PoS(NOW2016)076 Mo 100 3034 keV an endpoint, , higher beam currents, , 831598 (2014) = ββ νββ 2014 Q y. c/keV/kg/y was achieved with the 25 , 461 (1980)]. 3 10 − · 95B 5 10 · y at 90% CL could be set. With the full > 7 . 2 25 / 1 Ar at 270 MeV incident energy is investigated 10 T · 40 5 ) Mo, which has with 2 y is expected. . crystals combined with a Ge-wafer to detect both 5 Ne 100 4 26 18 > in , 10 2 · O / MoO 1 1 18 T ( νββ > 100 2 Ca , 1566 (1979). doi:10.1103/PhysRevLett.43.1566. / Ca 1 40 was demonstrated. A phased-approach is planned with AMoRE-I, T 43 40 , 132 (1988). doi:10.1016/0370-2693(88)91584-5. ]. To access the interesting cases for 0 ββ 203 19 , 141 (1985). doi:10.1016/0370-2693(85)90625-2. Q , 001 (2006) [hep-ph/0612311]. , 389 (1980) Erratum: [Phys. Lett. 93B 161B 2GC yr a limit of · decay is similarity complex, however DCE has the advantage to be accessible in and very similar transition operators. The description of NMEs extracted from . The idea is to measure the cross sections of Heavy-Ion-induced (HI) Double- The aim of the NUMEN Project is to access the nuclear matrix elements (NMEs) rel- AMoRE is searching for 0 νββ νββ νββ c/keV/kg/y and the expected sensitivity is 4 − doi:10.1155/2014/831598 [arXiv:1404.3751 [hep-ph]]. doi:10.1016/0370-2693(80)90349-4, 10.1016/0370-2693(80)90193-8. Currently, the DCE process An AMoRE Pilot ran underground with 5 crystals of 1.5 kg total mass. An energy resolution 10 · [1] S. Weinberg, Phys. Rev. Lett. [3] S. M. Boucenna, S. Morisi and J. W. F. Valle, Adv. High Energy[4] Phys. A. Zee, Phys. Lett. [5] A. Zee, Phys. Lett. [6] K. S. Babu, Phys. Lett. B [2] W. Grimus, PoS P References at INFN-Laboratori Nazionali del Sudcelerate Catania, the Italy. ions A and superconductingreaction a cyclotron products. MAGNEX is spectrometer used The to is experiment ac- could usedclear demonstrate structure to term that detect containing the and the cross measure matrixfor section elements the the factorization and relevant energy in a transitions a of nuclear [ nu- the reactiongaseous factor targets, and reasonably better holds energy resolutiontor will and be the needed. detector Substantial are upgradesisotope planned. of candidates First are the planned measurements accelera- for with 2016 an -for upgraded 2018. all system isotopes The final and of measurements interest a at are few high planned selected beam to intensity start and in 2021, after a major facility upgrade. DCE and 0 laboratory. NUMEN evant for 0 Charge-Exchange (DCE) reactions with high accuracy.states This as reaction has 0 the same initial and final Neutrino masses, states and interactions collected. An unprecedented background level of 0 AMoRE that lies above all natural-radioactivity-inducedis backgrounds. 9.6%. The AMoRE isotopic is abundance using of the of approximately 20 keV at exposure of 100 kg scintillation light and heat.scintillation-photon-induced heat Metallic in Magnetic the Calorimeters Ge-wafer and (MMC) the are heat increase used of both the to crystal itself. detect the consisting of 5 kg of crystalsof to be 200 operated kg from 2017 of to crystals,4 2019, followed to by be AMoRE-II, consisting operated from 2019 to 2024. The background goal of AMoRE-II is BEGe detectors. A half-life limit of PoS(NOW2016)076 , 085002 (2003) 67 6 , 2951 (1982). doi:10.1103/PhysRevD.25.2951. 25 4 042005. 91 02 020. 1502 JCAP Phys. Rev. D 2015 2015 et al et al , Article ID 293986 (2013). doi:10.1007/JHEP07(2014)081. doi:10.1140/epjc/s10052-016-4271-x. 2013 doi:10.1140/epja/i2015-15145-5. doi:10.1103/PhysRevD.67.085002 [hep-ph/0210389]. [9] Ludl, P.O. and Rodejohann, W. J. High Energ. Phys. (2016) 2016: 40. doi:10.1007/JHEP06(2016)040. [8] J. Schechter and J. W. F. Valle, Phys. Rev. D [7] L. M. 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