Presentation on theme: "Particle Physics and Astrophysics with Large Neutrino Detectors Pennsylvania State University Irina Mocioiu."— Presentation transcript:
Particle Physics and Astrophysics with Large Neutrino Detectors Pennsylvania State University Irina Mocioiu
Experiments IceCube/DeepCore: Cherenkov light in ice (South Pole) PINGU Antares: Cherenkov light in water (Mediteraneen) Pierre Auger: air showers (Argentina) radio Cherenkov: higher energy large underground neutrino detectors … Real data! + more to come
Sources some “guaranteed” high energy neutrinos: cosmic rays CMB GRB AGN Maybe: dark matter annihilation topological defects cosmic strings … Exactly how many? Where? What energies?
Lessons for particle astrophysics access to dense, violent environment test mechanism powering astrophysical sources cosmic ray acceleration processes cosmic ray propagation and intergalactic backgrounds … weak interactions Lessons for particle physics high energies, beyond those accessible in colliders, etc. weak interactions neutrino interaction cross-sections (in Standard Model!) neutrino properties new interactions/particles dark matter … complementary to photons and charged particles
Sources Propagation: flavor composition mostly decay not always: neutron decay, energy thresholds, energy losses, matter effects, magnetic fields energy dependent flavor ratios depend on neutrino and source properties neutrino oscillations over long distances decay + maximal mixing: different initial state: three flavor mixing important non-standard neutrino properties: decay, additional interactions, extra neutrinos, … change flavor composition/energy spectrum Interactions: in SM: cross section extrapolations, energy losses, flavor beyond SM: new interactions, LIV, new particles, dark matter, …
How to do it? o measure all you can o take into account everything you know/can think about o Identify the right observables energy distributions angular distributions flavor compositions better detector techniques smart tricks, unique signatures very good simulations correlations with other observables: photons, protons, etc. can distinguish particle physics from astrophysics effects learn about both
Ishihara, Nu 2012 IceCube sensitivity greatly improved
Nature 484, 351 (2012) Sullivan, Nu 2012 IceCube GRB search
Excluded models? Hummer, Baerwald, Winter (2012) He, Liu, Wang, Nagataki, Murase, Dai (2012) Not yet! Probing interesting parameter space Detailed analysis Energy dependence in spectra -> order of magnitude reduction in nrs
Outlook Neutrino telescopes now real: data! Getting better Just starting to get interesting now! High energy astrophysical neutrinos smoking gun for hadronic processes (few events for point source) need detailed analysis for data interpretation
IceCube Deep Core initial motivation: look for neutrinos from galactic sources, dark matter annihilation galactic center is above horizon at South Pole need to reduce large cosmic muon background coverage look at down-going events, study galactic sources, galactic center low energy threshold: opens the GeV neutrino energy range overlap with Super-Kamiokande at low energy and with IceCube at high energies
Atmospheric neutrinos Background to many searches lots of them > 50,000 events per year! somebody’s background is somebody else’s signal remember: solar neutrinos: solar physics, atmospheric neutrinos: proton decay expect: at low energies Super-Kamiokande IceCube Deep Core steep energy spectrum ( ) flux hard to measure at high energies
Three-flavor neutrino oscillations Three-flavor mixing matrix (in terms of Euler angles) We want to measure hierarchy (sign of ) CP violating phase Large effort to build new accelerator/reactor experiments beams: great control/precision; long time scales/high cost octant
Neutrino oscillations in the IceCube Deep Core tracks: -like fully contained events Angular distribution: Energy distribution: atmospheric flux normalization + main oscillation signal ( ) + matter effects (, hierarchy, CP) neutrino oscillations atmospheric neutrino flux Earth density profile ICDC physical mass: Effective mass in our analysis: (energy dependent) E. Fernandez-Martinez, G. Giordano, O. Mena, I. M. (2010) G. Giordano, O. Mena, I. M. (2010)O. Mena, I. M., S. Razzaque (2008);
ICDC atmospheric neutrinos Measure main oscillation parameters IceCube Deep Core: very large statistics contribution from multiple peaks Present: : MINOS : Super-Kamiokande E. Fernandez-Martinez, G. Giordano,O. Mena, I. M.(2010) Observable energy:
Normal versus inverted mass hierarchy fit to discriminate between normal and inverted hierarchy O. Mena, I. M., S. Razzaque (2008) much better now, with known and large E (GeV)
(Super-Kamiokande) (MINOS) Presently allowed values: IceCube Deep Core: Observable energies of 5 to 50 GeV 10 energy bins, 4 angular bins vs. 1st energy bin, 1 angular bin + 9 energy bins, 4 angular bins vs. Exclude first 2 energy bins: 8 energy bins, 4 angular bins vs completely free
IceCube Deep Core Expected allowed regions depend on the true values of the parameters and control of systematic uncertainties Neutrino oscillations: now important physics goal of ICDC -> PINGU
CC interactions: NC interactions: decay How about cascades? Earth diameter high energy (tau threshold effects small) background low: oscillations Looking for helped by:
Tau cascade rates or hadrons large present world sample of events: 5(9) DONUT + (2) (OPERA) Super-Kamiokande (after 15 years): high statistics interactions ICDC has already observed cascade events in the first small data sample direct evidence for appearance interaction cross-section non-standard interactions of experience with cascade detection
Mass Hierarchy in PINGU Akhmedov, Razzaque, Smirnov, 2012 in 5 years, depending on reconstruction systematics very general analysis, no details DIS only full analysis: likely better outcome! Mass Hierarchy in ICDC Agarwalla, Li, Mena, Palomares-Ruiz, 2012
PINGU - more physics than ICDC lower energy: better “shape” of first peak (precision) secondary peaks -> two mass scales contribute (CP violation+matter effect) - analysis more involved than ICDC better reconstruction/resolution atmospheric flux: transition between mu+pi and pi: -> flavor and energy dependence cross-sections: many contributions -> energy dependent uncertainties -> limited use of full kinematics: very useful with DIS in ICDC -> larger systematics/more work + outside input potentially very (cross section measurements, etc.)
Input from reactors, etc. Precision measurement of main oscillation parameters Above 10 GeV – nu tau cascades Matter effects – hierarchy few GeV – interference of two mass scales – CP phase theta_23 octant non-standard interactions – matter effects very useful information in combination with long baseline exp. What physics? What is needed: (Some) angular reconstruction: 3-4 bins sufficient Energy measurement: important to have few GeV and > 10GeV Flavor ID?
Atmospheric Neutrino Oscillations Large energy range: 100 MeV GeV Many baselines: 15 km – km cover large parameter space Complementary information Consistency checks very important Surprises? Is the three flavor oscillation picture the entire story? Are weak interactions the entire story? Long Baseline Neutrino Oscillation Experiments Fixed distance Good energy measurement Well known flux (near detector) good parameter determination
Sterile Neutrinos Model dependence: – 3+1 (6 angles), 3+2 (10 angles), 3+2+CP violation – angles: sterile mixing with,, – possible affect and differently If one present, expect the other No one to one correspondence between LSND/MiniBooNE (mu-e) and IceCube observations (mu-mu,mu-tau) Can constrain or discover oscillations at high mass scale for angles in the general range probed by MiniBooNE/LSND Cannot directly confirm/rule out MiniBooNE/LSND sterile nu interpretation
Sterile Neutrinos Cannot directly confirm/rule out MiniBooNE/LSND sterile nu interpretation except in specific/predictive models: Minimal 3+2 neutrino model - 4 massive mass eigenstates, 1 massless - 2 additional, right handed Weyl fields - 4 mixing angles + 3 phases Standard parameters+ 45angle+one extra phase - distortion of spectrum - large tau appearance D. Hollander, I.M.
Non-Standard Interactions (NSI) Matter effects in neutrino oscillations Very weak constraints in the sector Expected in connection with mass generation models, sterile neutrinos, etc. Parameterize our ignorance by most general form and try to constrain from data
Preliminary ε eτ - ε ττ Large correlations/degeneracy between parameters W. Wright, I.M.
Remember some history 1980’s: large detectors looking for proton decay, grand unification, etc.; atmospheric neutrinos are background atmospheric neutrino problem Atmospheric neutrinos: many uncertainties Beamline Proposals: MINOS 1995 OPERA 1998 ICARUS 1993 (detector), 1996 (neutrino oscillations) Super-Kamiokande (1998)
Long Baseline Neutrino Oscillation Experiments K2K (2000): confirmation of neutrino oscillations MINOS (2006): energy spectrum, best mass difference measurement OPERA: (2010) first tau candidate neutrino detection ICARUS: taking data T2K: taking data -> precision measurements, sub-dominant effects NOVA: under construction
Outlook IceCube Deep Core detector already taking data ! built to look for galactic sources, dark matter someone’s background can be someone else’s signal experiments take a very long time to construct/operate atmospheric neutrinos: huge statistics, many energies/distances use the data we already have and get the most of it! PINGU: huge, cheap, fast long baseline experiments: fixed baseline, limited energy range atmospheric neutrinos: many baselines, large energy range complementary information combined data: consistency checks expect SURPRISES!