A Yu Smirnov MaxPlanck Institut fur Kernphysik Heidelberg
A. Yu. Smirnov Max-Planck Institut fur Kernphysik, Heidelberg, Germany PASCOS 2021, June 14, 2021
Detector Source n 1 m n 2 m Wave packets of the eigenstates of propagation nim MEDIUM: Oscillations are separation of WP due to driven by different group velocities phase difference loss of coherence change between nim VEV, usual matter condensates, classical fields, new particles DM
Challenging theory: reformulations, reinterpretations, improvements, corrections, entanglement, quantumness Changing evolution equation: Oscillations at extreme conditions: Lorentz invariance violation, metric change, Equivalence principle violation high – low densities, high - low energies, dense neutrino background collective oscillations New interactions: NSI, long range forces, interaction with DM Searches for new neutrino states, sterile neutrinos
ults s e r l a t n e im r e p x e t n e Implications of rec Searches for sterile neutrinos Neutrino oscillatio ns and Standard m odel Neutrino oscillation s and phy sics BSM Focus on the topics related to physics projects in Korea - Reactor neutrinos, - Sterile neutrinos - Neutrinos and light dark sector
Dm 412 = 1 - 2 e. V 2 LSND
BOREXINO Collaboration (M. Agostini et al) Nature 587 (2020) 577 and 2105. 09211 [hep-ex] intermediate E-region 3. 5 s evidence of neutrinos from the CNO cycle Energy distribution of events BOREXINO After taking into account Collaboration (M. Agostini et al the MSW-effect Implications: astrophysics No additional suppression of the CNO flux on the top of MSW No new physics in the intermediate energy range
SK (also SNO+) observe the upturn of spectrum (SNO, SK) The D-N asymmetry at SK is reduced 3. 3% 2% Best fit value of Dm 212 from analysis of the solar neutrino data increased Descrepansy with Kam. LAND results reduced 2 s 1. 2 s 68%, 90%, 95%, 99%, 3 s CL contours Contours for solar models with different metallicity) also with and without DN effect (yellow)
See talk by A. Ichikawa Nu. Fit 5. 0 (2020) NOv. A T 2 K NOv. A: d. CP = 0. 82 p disfavors tension? d. CP = 1. 5 p by 2 s Difference can be related to different baselines and matter effects Reconcile with NSI or sterile neutrinos: S. Chatterje, A. Palazzo, 2008. 04161 [hep-ph], 2005. 103338 [hep-ph] Global fit: d. CP p bad news for measurements of CP- asymmetry
Ivan Esteban, et al, JHEP 2009 (2020) 178: 2007. 14792 [hep-ph] Data – more consistent, Analyses – stable, agreed Solar- Kam. LAND Dm 212 tension relaxed (AND, upturn, CNO-BOREXINO) d. CP = 197 +27/-240 (NO) close to (consistent with ) p Preference of NO is less significant Significance of deviation of 2 -3 mixing from p/4 is less profound Solid (dashed) – without (with) adding SK atmospheric
Hanbit Nuclear Power Plant: 6 reactors RENO Collaboration, 2010. 14989 [hep-ex] ne spectrum from unfolding: a measured IBD prompt spectrum vs. Huber-Mueller (HM) prediction The oscillation effect is removed using the measured q 13 to obtain the spectrum at reactor. The ne event rates as a function of the distance from a reactor, relative to the HM (Huber Mueller) prediction. IBDyield/HM 0. 941 ± 0. 019 RAA
V. Kopeikin, et al. 2103. 01684 [nucl-ex] Re-evaluating reactor antineutrino spectra with new measurements of the ratio between 235 U and 239 Pu spectra ILL measurements of IBD spectrum, inversion n – spectrum, with various corrections 5 -10% up KI – Kurchatov institute Ratio of cumulative spectra R = S 5 /S 9 If correct - RAA disappears
NEOS Collaboration Z. Atif et al 2011. 00896 [hep-ex] Search for sterile neutrino oscillation using RENO and NEOS data RENO prediction for NEOS vs. NEOS observed prompt spectrum. NEOS extracted νe spectrum. The areas of two spectra are normalized for a shape comparison. Error bars – statistical, band - systematics
NEOS Collaboration Z. Atif et al 2011. 00896 [hep-ex] Bounds on oscillation parameters the RENO and NEOS combined search (black) The best fit values (green circle) : Dm 142 = 2. 37 e. V 2 sin 22 q 14 = 0. 09 NEOS 90% C. L. (gray shaded), PROSPECT 95% C. L. (red) RENO near/far -blue RAA (dotted): Dm 142 = 2. 4 e. V 2 Before: Daya. Bay/NEOS: Dm 142 = 1. 73 e. V 2 sin 22 q 14 = 0. 05 another wiggle. .
Stereo Collaboration (M. Licciardi ) 2105. 13776 [hep-ex] Stereo NEUTRINO-4 PROSPECT
RAA M. Danilov, 2012. 10255 [hep-ex] Ratio of e+ energy spectra measured at the bottom and top detector positions (statistical errors only) b. f. (red): Dm 142 = 1. 3 e. V 2 sin 22 q 14 = 0. 02 Exclusion area at 90% C. L. obtained with the Gaussian method Spread of b. f. Points from different experiments
C. Giunti, et al, P. L. B 816 (2021) 136214 2101. 06785 [hep-ph] Deep study of the data Energy resolution of the detector, more reliable Monte Carlo simulation: Significance reduces: 3 s 2. 2 s b. f. point moves to maximal mixing Strong tension with the KATRIN, PROSPECT, STEREO, solar νe bounds
Ajimura, S. et al. 2012. 10807 [hep-ex] 2104. 13169 [physics. ins-det] 17 t LS + Gd J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source (at Material Life Facility MLF) Repeating LSND: m–decay at rest, searches for nm - ne oscillations JSNS 2 operates now Sensitivity of JSNS 2 and upgrade JSNS 2 -II: second detector at 48 m ICARUS at Fermilab detects first events
Dm 412 = 1 - 2 e. V 2 LSND
x –t space: separation of the WP E-p space: integration over the energy uncertainty sx s. E Results in suppression of interference Equivalence due to sx ~ 1/s. E sx D vg Coherence length: Lcoh = Difference of group velocities vgi = d. Hi /dp In vacuum: L. Stodolsky Dvg = Dm 2/2 E 2 Lcoh = sx Dm 2
A de Gouvea, V De Romeri, C. A. Termes, 2104. 05806 [hep-ph] Bound on size of the WP Daya Bay, RENO Averaging effect Absence of decoherence (averaging) effects: Dm 2 L << Lcoh sx > L 2 E 2 Analysis of data: Expected: sx > 2. 1 10 -11 cm sx ~ 10 -9 cm Kam. LAND
S. P. Mikheyev, A. Y. S. Matter changes group velocities vi Lcoh Y. P. . Porto-Silva , A Y S 2103. 10149 [hep-ph] Constant density At certain E 0 Lcoh infty corresponds to equality of the group velocities: Dv = v 2 m - v 1 m = 0 no separation of the wave packets E 0 coincides with the MSW resonance in oscillations of mass states MSW resonance energy of flavor oscillations At high densities the coherence length as in vacuum Lcohm Lcoh/cos 2 q ~ Lcoh
Y. P. . Porto-Silva , A Y S 2103. 10149 [hep-ph] Periodic modulations n n. R + - + adiabatic n - + Dv changes the sign Castle wall profile Adiabaticity violation Number of coherence periods Several Einf associated with parametric resonances Applications to SN neutrino collective oscillations x
Dm 412 = 1 - 2 e. V 2 LSND
SM n. R Neutrino Higgs portals Interactions affect oscillations Neutrinos provide probes of the light dark sector Dark sector scalars, f fermions, c vector bosons, g Dark photons Sterile neutrinos Axions, Majorons, DM Refraction, elastic forward scattering, q 2 = 0 V ~ g 2 /mmed 2 do not disappear when g , mmed 0 in contrast to inelastic interactions ~ g 2/qmin 2
A. S. , V. Valera, to appear L = g n. L c f + h. c. g < 10 -7 c n. L f c* c* (1 - e) (y - 1)2 + x 2 VB = ½V 0 = f g 2 2 mf 2 (nc + nc) y = E/ ER n. L c + 1+e y+1 Resonance: y = 1 Corresponds to s = m f 2 ER = mf 2/2 mc in SM: due to Z, W C. Lunardini, A. S. Neutrino scattering on background fermions c with scalar f mediator Asymmetry of bgr: e = (nc – nc)/(nc + nc) nc and nc – the number densities of c and c* Width of resonance x = G / ER g 2 G= m 4 p f
S. F Ge and H Murayama, 1904. 02518 [hep-ph] n. L f* 2012. 09474 [hep-ph] f. R f* (s - mf 2) n Vs ~ (s - mf 2 )2 + s G 2 G= f n. L f. R Ki-Yong Choi, Eung Jin Chun, Jongkuk Kim, 1909. 10478 [hep-ph] f Vu ~ n. L n u - m f 2 g 2 m f 32 p Resonance: s = mf 2 ER = mf 2/2 mf Neutrino scattering on DM particles f (target) with f. R - mediator n and n – the number densities of f and f*
A. S. , V. Valera, to appear Outside the peak: |y - 1| >> x VB = V 0 Vvac = Dm 2/2 E VRvac = Dm 2/2 ER = VRvac /y y-e y 2 - 1 y=0 VB/V 0 e y inf 1 /y e=1 1 /(y + 1) e=0 y/(y 2 - 1) e=-1 1 /(y - 1) Relative contribution of the background and vacuum terms r = V 0/VRvac
A. S. , V. Valera, to appear or effective kinetic term Ve = 2 GFne - usual matter potential - shift of the usual MSW resonance 2 new resonances in n-channel 2 new resonances in anti nchannel Boxes - MSW resonances Effective mass squared difference Dmeff 2 = 2 E(Vvac +VB ) = Dm 2 (1 + VB/Vvac)
Moduli | Dmeff 2 /Dm 2| as function of y for different r = V 0/VRvac A. S. , V. Valera, to appear Short baseline The oscillation phase: Dmeff 2 F = 2 E L = Dm 2 Fvac Lines: 1/Fvac long baseline their crossing with Dmeff 2 /Dm 2 corresponds to F = 1 Above the lines F (y) > 1 and the oscillation effect is large With increase of r the y-region of strong effect expands
Oscillation probability P = sin 2 2 q sin 2 F/2 Signatures: - dip, - bump (after averaging fast oscillations), - tail Mini. Boo. NE excess - due to bump for relatively small L, so that apart from resonance region 200 -400 Me. V the phase and oscillations effect are small. J. Asaadi et al. , PRD 97, 7, 2470, (2018) MB A. S. , V. Valera, to appear
A. S. , V. Valera, to appear Based on dependence on energy of Dmeff 2 (E) It is expected that reactors Dmeff 2 (E << ER ) = Dm 2 MB explanation requires r > 1. 6 Data are consistent with Dmeff 2 = const and r < 0. 01 Dmeff 2 (E >> ER ) = r Dm 2
C. Lunardini, A. S. Ki-Yong Choi, Eung Jin Chun, Jongkuk Kim, 2012. 09474 [hep-ph], 2 1 E has the same behaviour as the kinetic (mass) term Dm /2 E At E >> ER (y >> 1) the potential VB ~ It is the appearance of 1/E term in the Hamiltonian of evolution equation that allowed to conclude that the oscillations imply the mass (coupling of neutrinos with VEV) 1/E is a general dependence at large E, does not depend on the nature of mediator and target The conditions for 1/E dependence: 1. Light mediator: mmed << 2 Emtar 2. Light target: mtar << E
Effective neutrino mass due to interactions meff 2~ g 2 nc 4 mc Condition for 1/E dependence (mass) has been checked down to 0. 1 Me. V Therefore ER << Eobs ~ 0. 1 Me. V The effective mass depends on energy of neutrino and number density of scatterers Therefore meff can be different in different space –time points, in contrast to the standard mass due to coupling to VEV (does not depend on z) meff (z) ~ n(z) = n 0 (1 + z)3 The effective mass increased in the past in contrast to standard generated by VEV. Problem in Cosmology?
meff (z) ~ [x (1 + z)3 ]1/2 meff (loc) where 1/x ~ 105 - local (near the Earth) over-density of the background In the epoch of matter-radiation equality, z = 1000, DM should already be formed and structures start to form. meff (1000) ~ 5 e. V For meff (loc) = 0. 05 e. V and 1/x ~ 105 - violates cosmological bound on the sum of neutrino masses For not very small ER one should take into account dependence (decrease) of meff (loc) with neutrino energy Dmeff 2(E) ~ y(y - e) Dm 2 2 y -1 and for relic neutrinos meff (loc) can be very small y = E/ER
|Dmeff 2| ER = mf 2/2 mc e=0 For e = 0 decrease of mass with E is even stronger existing observations ER Below resonance: meff 2(<< ER) = meff E 2(>> E E 2 ER) =m ER ER Suppose ER = 0. 01 Me. V For relic nu E = 10 -4 e. V : meff < 5 10 -6 e. V CMB bound is satisfied For KATRIN: E = 1 e. V: meff < 2 10 -4 e. V - not measurable
Dm 412 = 1 - 2 e. V 2 LSND
Anomalies and tensions found in different oscillation experiments lose sigmas and disappear, in particular the case of sterile neutrino become weaker Standard oscillation picture holds: no deviations found no new interactions effects, no dependence of the oscillation parameters, (masses and mixing) on energy, time, and fundamental C- conjugation (CPT) observed Possible interactions of neutrinos with light dark sector explored. Neutrino oscillations experiments probe this sector For very small couplings and masses the refraction provides the most sensitive tests - resonance refraction at low energies - possibility to substitute usual neutrino mass by interactions with medium
Dm 412 = 1 - 2 e. V 2 LSND
Ki-Yong Choi, Eung Jin Chun, Jongkuk Kim, A. S. Bound from 1/E dependence mf > m f mf < 2 mf. EB mf, e. V EB = 0. 1 Me. V Red lines – lower bounds on masses of DM and mediator from Lya - data for different values of g mf, e. V Lower bound on values of mf and mf that can reproduce the observed oscillation effects mf < 10 -4 e. V Bounds: mf < 10 -13 e. V g < 10 -12
First Double Chooz θ 13 Measurement via Total Neutron Capture Detection - Double Chooz Collaboration (de Kerret, H. et al. ) ar. Xiv: 1901. 09445 [hep-ex] The most precise published reactor measurements of θ 13 from DC MD Tn. C , DYB and RENO. DC result shows a [25, 48]% higher central value whose significance ranges [1. 3, 1, 9]σ compared to other reactor measurements. The T 2 K larger uncertainty is due to the marginalisation over θ 23 and CP violation.
DANSS The same parameters as in NEOS Ratio of the data to the expected Daya Bay spectrum. The solid green line - the best fit. The dashed red line corresponds to the RAA best fit parameters Ko: 2016, et al. Ratio of positron energy spectra measured at the bottom and top detector positions (stat. errors only). Dashed curve - the three active neutrino case, the red solid curve - the best fit in (3+1) case, the black dotted curve is the RAA expectation.
L/E dependence for Neutrino-4 data points vs. expected oscillation signal for the best fit values (red dots), Serebrov 2019.
T 2 K-2
3 a Comparisons of 3ν non-oscillating ν¯¯¯e spectra at reactor source among RENO, NEOS and Daya Bay. The differences of fission fractions are corrected. Statistical uncertainties and systematic uncertainties are combined and represented as the error bars. Note that the reactor related uncertainty is not included (no) in the errors of RENO/NEOS, while Daya-Bay/RENO and Daya-Bay/NEOS include reactor uncertainty.
Take from Pontecorvo school
Joel Kostensalo et al 1906. 10980 [nucl-th] New cross-section calculations using nuclear shell-model wave functions obtained by exploiting recently developed two-nucleon interactions. The significance of anomaly decreases from 3. 0σ to 2. 3σ. The result is compatible with indication of short-baseline νe disappearance from NEOS and DANSS data. Gallium data with the JUN 45 cross sections vs. the allowed regions from NEOS, DANSS and PROSPECT reactor experiments
SNO+ Collaboration (Anderson, M. et al. ) Phys. Rev. D 99 (2019) no. 1, 012012 1812. 03355 [hep-ex] Water phase: Measurement of the 8 B solar neutrino flux in SNO+ with very low backgrounds S/B ~ 4, E > 6 Me. V 114. 7 days of data Hint of upturn? Distribution of event directions wrt. solar direction The extracted event rate as function of reconstructed electron kinetic energy 69. 2 kt-day dataset Flux: 2. 53 [-0. 28+0. 31(stat) -0. 10+0. 13(syst)] x 10 -6 cm -2 s-1
S. F. Ge , H. Murayama, E. J. Chun, Ki-Yong Choi, Jongkuk Kim, A. S. E dependence of V follows from propagator of mediator: 1 V~D~ (pmed 2 - mmed 2) mass of mediator 1 D reduces to D ~ +/mass of target particle 2 Emtar where +/- correspond to scattering in s/u-channel under conditions of mmed 2 2 << p 2 m or E >> 1. Light mediator: med 2 mtar mmed << 2 Emtar 2. Light target: mtar << E +/- for s/u channels no cancellation of V in C-symmetric medium.
2006. 15208 [ex-ph]
Hanbit Nuclear Power Plant: 6 reactors August 2011 - March 2020 ne candidate events ND: 966 094 (2. 39% bkgr) FD: 116 111 (5. 13% bkgr)
L. Berns (T 2 K Collaboration) Update with 3. 6 1021 P. O. T. Constrains on oscillation parameters The CP phase ellipses of predictions In the n - barn plane for different values of 2 -3 mixing 0. 55 0. 50 0. 45
RENO Collaboration, 2010. 14989 [hep-ex] ne spectrum from unfolding: a measured IBD prompt spectrum vs. Huber-Mueller (HM) prediction The oscillation effect is removed using the measured q 13 to obtain the spectrum at reactor. The two spectra are normalized outside the 6 Me. V excess region This spectrum used to search for steriles at NEOS
Overall assessment Good agreement between oscillation parameters Dm 322 , Dm 212, q 12 , q 13 , q 32 determined from different experiments with different energies, medium properties with neutrino and antineutrinos No dependence of these parameters on energy or time is found Situation is more uncertain (fragile) with octant of q 23 , mass ordering and the phase d. CP Existence of sterile neutrinos, is still under investigation although their case becomes weaker
Proposal of an underground neutrino detector in Korea 260 kton (187 kton FV) water Cherenkov detector with wide capacities. Possible site: under Mt. Bisul It can serve as the second detector of Hyper-Kamiokande LBL experiment with J- PARC neutrino beam: the distance 1088 km, of-axis angle 1. 3 o Improvements of measurement of neutrino oscillation parameters: leptonic CP phase and the neutrino mass ordering.
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