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Testing origin of neutrino mass and mixing Hitoshi Murayama (Berkeley/IPMU) KITPC, September 16, 2008 With Matt Buckley Slide 2 New intl research institute in Japan astrophysics particle theory particle expt mathematics official language: English >30% non-Japanese $13M/yr for 10 years launched Oct 1, 2007 25 now, >40 in fall excellent new faculty hires, young and dynamic! will hire about 30 more scientists new building in 2009 intl guest house in 2009 wkshp ~once a month Slide 3 Science For the committee: What is the Universe made of? How did it start? What is its fate? What are its fundamental laws? Why do we exist? translation for scientists: nature of dark matter resolving space-like singularity w of dark energy unified theory, p-decay origin of baryon asymmetry, neutrinos Murayama, KITPC, 9/16/2008 Slide 4 IPMU initiatives in experiments Vagins: let SuperK detect relic supernova with Gd Kozlov: use KamLAND to see if = with Xe Suzuki/Nakahata/Martens : XMASS to detect dark matter Aihara/Takada/Yoshida: HyperSuprimeCam at Subaru and data analysis to study dark energy billions of years _ Also photo detector development for future experiments Murayama, KITPC, 9/16/2008 Slide 5 Proposed Centers ~one hour from much of Tokyo Also a satellite in Kamioka Komaba Campus 30 km Narita Airport Where it is IPMU KEK Tsukuba Express Murayama, KITPC, 9/16/2008 Slide 6 Slide 7 Winter 2009 occupancy ~5900m 2 Murayama, KITPC, 9/16/2008 Slide 8 emphasis on large interaction area like a European town square ~400 m 2 Murayama, KITPC, 9/16/2008 Slide 9 Full-time Scientists non-Japanese 50% Expect ~15-20 positions this year Check out www.ipmu.jpwww.ipmu.jp Murayama, KITPC, 9/16/2008 Slide 10 Testing origin of neutrino mass and mixing Hitoshi Murayama (Berkeley/IPMU) KITPC, September 16, 2008 With Matt Buckley Slide 11 Murayama, KITPC, 9/16/2008 The Question Neutrino physics has been full of surprises Weve learned a lot in the last ~8 years We want to learn more What exactly can we learn from neutrinos? Origin of neutrino mass? Origin of baryon asymmetry? Origin of universe? Slide 12 Murayama, KITPC, 9/16/2008 The Question The seesaw mechanism has been the dominant paradigm for the origin of tiny neutrino mass Physics close to the GUT scale How do we know if it is true? Is there a way to test it experimentally? Short answer: No However, we can be convinced of it Slide 13 Murayama, NNN '08, Paris POSSIBLE Slide 14 Murayama, KITPC, 9/16/2008 How can it be possible at all? We can (hope to) do good measurements on observables at low energies (meVTeV) If we know something about the boundary conditions at high energies, we can say something non-trivial about physics between the two energy scales We have to be very lucky to be able to do this Need the whole planets lined up! Slide 15 Murayama, KITPC, 9/16/2008 Alignment of the Planets Slide 16 Murayama, KITPC, 9/16/2008 Outline Why Neutrinos? The Big Questions Seesaw and SUSY-GUT Experimental Tests Conclusion Slide 17 Why Neutrinos? Slide 18 Murayama, KITPC, 9/16/2008 Interest in Neutrino Mass So much activity on neutrino mass already. Why am I interested in this? Window to (way) high energy scales beyond the Standard Model! Slide 19 Murayama, KITPC, 9/16/2008 Why Beyond the Standard Model Standard Model is sooooo successful. But none of us are satisfied with the SM. Why? Because it leaves so many great questions unanswered Drive to go beyond the Standard Model Two ways: Go to high energies Study rare, tiny effects Slide 20 Murayama, KITPC, 9/16/2008 Rare Effects from High-Energies Effects of physics beyond the SM as effective operators Can be classified systematically (Weinberg) Slide 21 Murayama, KITPC, 9/16/2008 Unique Role of Neutrino Mass Lowest order effect of physics at short distances Tiny effect (m /E ) 2 ~(0.1eV/GeV) 2 =10 20 ! Inteferometry (i.e., Michaelson-Morley) Need coherent source Need interference (i.e., large mixing angles) Need long baseline Nature was kind to provide all of them! neutrino interferometry (a.k.a. neutrino oscillation) a unique tool to study physics at very high scales Slide 22 Murayama, KITPC, 9/16/2008 Ubiquitous Neutrinos They must have played some important role in the universe! Slide 23 Murayama, KITPC, 9/16/2008 The Data de Gouvas classification: Indisputable Atmospheric Solar Reactor strong Accelerator (K2K) And we shouldnt forget: unconfirmed Accelerator (LSND) Slide 24 Murayama, KITPC, 9/16/2008 Historic Era in Neutrino Physics We learned: Atmospheric s are lost. P=4.2 10 26 (SK) (1998) converted most likely to (2000) Solar e is converted to either or (SNO) (2002) Only the LMA solution left for solar neutrinos (Homestake+Gallium+SK+SNO) (2002) Reactor anti- e disappear (2002) and reappear (KamLAND) (2004) Slide 25 Murayama, KITPC, 9/16/2008 What we learned Lepton Flavor is not conserved Neutrinos have tiny mass, not very hierarchical Neutrinos mix a lot the first evidence for incompleteness of Minimal Standard Model Very different from quarks Slide 26 Murayama, KITPC, 9/16/2008 Neutrinos do oscillate! Proper time Slide 27 Murayama, KITPC, 9/16/2008 Typical Theorists View ca. 1990 Solar neutrino solution must be small angle MSW solution because its cute Natural scale for m 2 23 ~ 10100 eV 2 because it is cosmologically interesting Angle 23 must be ~ V cb =0.04 Atmospheric neutrino anomaly must go away because it needs a large angle Wrong! Slide 28 Murayama, KITPC, 9/16/2008 The Big Questions What is the origin of neutrino mass? Did neutrinos play a role in our existence? Did neutrinos play a role in forming galaxies? Did neutrinos play a role in birth of the universe? Are neutrinos telling us something about unification of matter and/or forces? Will neutrinos give us more surprises? Big questions tough questions to answer Slide 29 Seesaw and SUSY-GUT Slide 30 Murayama, KITPC, 9/16/2008 Seesaw Mechanism Why is neutrino mass so small? Need right-handed neutrinos to generate neutrino mass To obtain m 3 ~( m 2 atm ) 1/2, m D ~m t, M 3 ~10 14 GeV, but R SM neutral Slide 31 Murayama, KITPC, 9/16/2008 Grand Unification electromagnetic, weak, and strong forces have very different strengths But their strengths become the same at ~2 10 16 GeV if supersymmetry To obtain m 3 ~( m 2 atm ) 1/2, m D ~m t M 3 ~10 14 GeV! M3M3 Slide 32 Leptogenesis You generate Lepton Asymmetry first. (Fukugita, Yanagida) Generate L from the direct CP violation in right-handed neutrino decay L gets converted to B via EW anomaly More matter than anti-matter We have survived The Great Annihilation Despite detailed information on neutrino masses, it still works (e.g., Bari, Buchmller, Plmacher) Murayama, KITPC, 9/16/2008 Slide 33 Origin of Universe Maybe an even bigger role: inflation Need a spinless field that slowly rolls down the potential oscillates around it minimum decays to produce a thermal bath The superpartner of right-handed neutrino fits the bill When it decays, it produces the lepton asymmetry at the same time (HM, Suzuki, Yanagida, Yokoyama) Decay products: supersymmetry and hence dark matter Neutrino is mother of the Universe? ~ amplitude size of the universe R t t Slide 34 Experimental Tests Slide 35 Murayama, KITPC, 9/16/2008 Can we prove it experimentally? Short answer: no. We cant access physics at >10 10 GeV with accelerators directly But: we will probably believe it if the following scenario happens Archeological evidences Slide 36 Murayama, KITPC, 9/16/2008 We should push this U e3 is not too small At least makes it plausible that CP asymmetry in right-handed neutrino decay is not unnaturally suppressed CP violation in neutrino oscillation At least proves that CP is violated in the lepton sector But need more fossils to fill missing links Slide 37 LHC is here Murayama, KITPC, 9/16/2008 Slide 38 A scenario to establish seesaw LHC finds SUSY, ILC establishes SUSY no more particles beyond the MSSM at TeV scale Gaugino masses unify (two more coincidences) Scalar masses unify for 1st, 2nd generations (two for 10, one for 5*, times two) strong hint that there are no additional particles beyond the MSSM below M GUT except for gauge singlets. Slide 39 Murayama, KITPC, 9/16/2008 Gaugino and scalars Gaugino masses test unification itself independent of intermediate scales and extra complete SU(5) multiplets Scalar masses test beta functions at all scales, depend on the particle content Kawamura, HM, Yamaguchi Slide 40 Murayama, KITPC, 9/16/2008 gauginos, higgsinos charged ones charginos neutral ones neutralinos Slide 41 Murayama, KITPC, 9/16/2008 Slide 42 Slide 43 Model-independent parameter determination Chargino/neutralino mass matrices have four parameters M 1, M 2, , tan Can measure 2+4 masses can measure 10x2 neutralino cross sections can measure 3x2 chargino cross sections depend on masses of Murayama, KITPC, 9/16/2008 Slide 44 A scenario to establish seesaw Next generation experiments discover neutrinoless double beta decay Say, m ee ~0.1eV There must be new physics below ~10 14 GeV that generates the Majorana neutrino mass But it can also happen with R-parity violating SUSY Slide 45 Murayama, KITPC, 9/16/2008 A scenario to establish seesaw It leaves the possibility for R-parity violation Consistency between cosmology, dark matter detection, and LHC/ILC will remove the concern Slide 46 Murayama, KITPC, 9/16/2008 Need New Physics