118695560
First results from the MuLan and MuCap experiments
MuLan and MuCap are ongoing experiments at the Paul Scherrer Institut, Switzerland, that use the muon lifetime to determine fundamental weak interaction parameters. The goal of MuLan is a 1 ppm measurement of the positive muon lifetime τμ+ to determine the Fermi constant GF to 0.5 ppm. The goal of MuCap is to make a 1% determination of the rate ΛS of the process of nuclear muon capture by the proton, μp→nν, by measuring the μ− disappearance rate in hydrogen gas to 10 ppm and subtracting the world average for the μ+ decay rate. A 1% determination of the capture rate ΛS is of interest because it would enable a 7% determination of gP, the induced pseudoscalar coupling of the nucleon. In 2007, both experiments published first results based upon data collected by each in 2004. MuLan reported an 11 ppm μ+ lifetime measurement, τμ+ = 2.197 013(24) μs, resulting in a new, 9.6 ppm world average, τμ+ = 2.197 019(21) μs, which determines the Fermi constant, GF = 1.166 371(6)×10−5 GeV−2, to 5 ppm. MuCap reported a 3%...
42385898
Production of Radioactive Isotopes through Cosmic Muon Spallation in KamLAND
Radioactive isotopes produced through cosmic muon spallation are a background for rare-event detection in ν detectors, double-β-decay experiments, and dark-matter searches. Understanding the nature of cosmogenic backgrounds is particularly important for future experiments aiming to determine the pep and CNO solar neutrino fluxes, for which the background is dominated by the spallation production of ^(11)C. Data from the Kamioka liquid-scintillator antineutrino detector (KamLAND) provides valuable information for better understanding these backgrounds, especially in liquid scintillators, and for checking estimates from current simulations based upon MUSIC, FLUKA, and GEANT4. Using the time correlation between detected muons and neutron captures, the neutron production yield in the KamLAND liquid scintillator is measured to be Y_n=(2.8±0.3)×10^(-4) μ^(-1) g^(-1) cm^2. For other isotopes, the production yield is determined from the observed time correlation related to known isotope lifetimes. We find some yields are inconsistent with extrapolations based on an accelerator muon beam experiment.
119144377
A circulating hydrogen ultra-high purification system for the MuCap experiment
Abstract The MuCap experiment is a high-precision measurement of the rate for the basic electroweak process of muon capture, μ − +p→n+ ν μ . The experimental approach is based on an active target consisting of a time projection chamber (TPC) operating with pure hydrogen gas. The hydrogen has to be kept extremely pure and at a stable pressure. A Circulating Hydrogen Ultra-high Purification System was designed at the Petersburg Nuclear Physics Institute (PNPI) to continuously clean the hydrogen from impurities. The system is based on an adsorption cryo pump to stimulate the hydrogen flow and on a cold adsorbent for the hydrogen cleaning. It was installed at the Paul Scherrer Institute (PSI) in 2004 and performed reliably during three experiment runs. During several months long operating periods the system maintained the hydrogen purity in the detector on the level of 20 ppb for moisture, which is the main contaminant, and of better than 7 and 5 ppb for nitrogen and oxygen, respectively. The pressure inside the TPC was stabilized to within 0.024% of 10 bar at a hydrogen flow rate of three standard liters per minute.
41701681
Measurement of the 8B solar neutrino flux with the KamLAND liquid scintillator detector
We report a measurement of the neutrino-electron elastic scattering rate from ^8B solar neutrinos based on a 123 kton-day exposure of KamLAND. The background-subtracted electron recoil rate, above a 5.5-MeV analysis threshold is 1.49 ± 0.14(stat) ± 0.17(syst) events per kton-day. Interpreted as due to a pure electron flavor flux with a ^8B neutrino spectrum, this corresponds to a spectrum integrated flux of 2.77 ± 0.26(stat) ± 0.32(syst) ×10^6 cm^(−2_s^(−1). The analysis threshold is driven by ^(208)Tl present in the liquid scintillator, and the main source of systematic uncertainty is due to background from cosmogenic ^(11)Be. The measured rate is consistent with existing measurements and with standard solar model predictions which include matter-enhanced neutrino oscillation.
55856903
Sensitivity of CUORE to Neutrinoless Double-Beta Decay
Sensitivity of CUORE to Neutrinoless Double-Beta Decay b c,:L d e f F . Alessandria , E . A n d r e o t t i ' , R. A r d i t o , C. Arnaboldi , F . T. Avignone IIP , M . B a l a t a , I. Bandac , T. I. Banks ' ' , G . B a r f , J . Beeman , F . Bellini ' , A . Bersani , M . Biassoni ' , T. Bloxham , C. Brofferio ' , A . Bryant , C. B u c c i , X . Z. C a i , L . C a n o n i c a , S. C a p e l l i , L . Carbone , L . Cardani ' , M . Carrettoni , N . Casali ' , N . Chott , M . Clemenza ' , C. Cosmelli ' , O. Cremonesi , R. J . Creswick , I. Dafinei , A . Dally , A . De B i a s i , M . R Decowski ' ' , M . M . Deninno , A . de Waard , S. D i D o m i z i o ' , L . Ejzak '*, R. Faccini ' , D. Q. Fang , H . A . Farach , E . Ferri '°, F . Ferroni , E . F i o r i n i , L . F o g g e t t a ' ° , M . A . Franceschi*, S. J . Freedman G . Frossati , B . K . Fujikawa , A . Giachero , L . Gironi '°, A . Giuliani , P. G o r l a , C. G o t t i , E . Guardincerri , T. D . Gutierrez , E . E . H a l l e r ' , K . Han , K . M . Heeger , H . Z. Huang*', K . Ichimura , R. KadeP, K . K a z k a z , G . KeppeT, L . Kogler ' , Y u . G . Kolomensky ' , S. K r a f t ' , D . Lenz , Y . L . L i , X . L i # , E . Longo ' , Y . G . M a . C. M a i a n o ' , G . M a i e r , M . M a i n o ' , C. Mancini ' , C. Martinez , M . M a r t i n e z , R. H . M a r u y a m a , N . Moggi , S. Morganti , T. Napolitano*, S. Newman ' , S. N i s i , C. N o n e s ' ' , E . B . N o r m a n ' , A . N u c c i o t t i ' , F . O r i o , D. O r l a n d i , J . L . Ouellet ' , M . Pallavicini ' , V . Palmieri , L . Pattavina , M . P a v a n ' , M . P e d r e t t i , G . Pessina , S. P i r r o , E . P r e v i t a l i , V . Rampazzo , F . R i m o n d i J , C. Rosenfeld , C. Rusconi , C. S a l v i o n i , S. Sangiorgio '*, D . Schaeffer ' , N . D . Scielzo , M . S i s t i ' , A . R. S m i t h , F . Stivanello , L . Taffarello , G . Terenziani , W . D . T i a n , C. Tornei , S. Trentalange*', G . V e n t u r a ' , M . Vignati ' , B . S. W a n g ' , H . W . W a n g , C. A . Whitten J r . - \ T. Wise . A . Woodcraft , N . X u , L . Z a n o t t i ' , C. Zarra , B . X . Zhu*', S. Zucchelli J k e j w k x c c e , c b e c ab ah c (CUORE e a a c a c j e c c m aa c b,c aa,q af e a c q a a f ae a8 c ad, aa aa c e c n v e f p d e,c b c e e e c f c e s e e,c c f p,n f v ad Collaboration) a INFN - Sezione di Milano, Milano 1-20133 - Italy di Fisica e Matematica, Universita dell'Insubria, Como 1-22100 - Italy INFN - Sezione di Milano Bicocca, Milano 1-20126 - Italy Dipartimento di Ingegneria Strutturale, Politecnico di Milano, Milano 1-20133 - Italy Dipartimento di Fisica, Universita di Milano-Bicocca, Milano 1-20126 - Italy fDepartment of Physics and Astronomy, University of South Carolina, Columbia, SC 29208 - USA INFN - Laboratori Nazionali del Gran Sasso, Assergi (L'Aquila) 1-67010 - Italy Department of Physics, University of California, Berkeley, CA 94720 - USA 'Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94-720 - USA UN FN - Sezione di Bologna, Bologna 1-40127 - Italy Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 - USA 'Dipartimento di Fisica, Sapienza Universita di Roma, Roma 1-00185 - Italy INFN - Sezione di Roma, Roma 1-00185 - Italy INFN - Sezione di Genova, Genova 1-16146 - Italy Shanghai Institute of Applied Physics (Chinese Academy of Sciences), Shanghai 201800 - China Dipartimento di Fisica, Universita di Genova, Genova I-I6I46 - Italy Department of Physics, University of Wisconsin, Madison, WI 53706 - USA INFN - Laboratori Nazionali di Legnaro, Legnaro (Padova) 1-35020 - Italy Kamerlingh Onnes Laboratorium, Leiden University, Leiden, RA 2300 - The Netherlands INFN - Laboratori Nazionali di Frascati, Frascati (Roma) 1-00044 - Italy Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, 914-05 Orsay Campus - France b Dipartimento C d g h k M p q r f INFN - Sezione di Roma Tor Vergata, Roma 1-00133 - Italy ' 'Physics Department, California Polytechnic State University, San Luis Obispo, CA 934-07 - USA ^Department of Materials Science and Engineering, University of California, Berkeley, CA 94-720 - USA Department of Physics and Astronoma, University of California, Los Angeles, CA 90095 - USA Physics Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94-720 - USA Lawrence Livermore National Laboratory, Livermore, CA 94-550 - USA Laboratorio de Fisica Nuclear y Astroparticulas, Universidad de Zaragoza, Zaragoza 50009 - Spain Department of Nuclear Engineering, University of California, Berkeley, CA 94-720 - USA Dipartimento di Fisica, Universita di Bologna, Bologna 1-4-0127 - Italy EH&S Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94-720 - USA flNFN - Sezione di Padova, Padova 1-35131 - Italy Dipartimento di Fisica, Universita di Firenze, Firenze 1-50125 - Italy INFN - Sezione di Firenze, Firenze 1-50125 - Italy SUPA, Institute for Astronoma, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ - UK v aa ab ac ad ae a ag ah al * C o r r e s p o n d i n g author Email addresses: e j z a k 8 w i s c . e d u ( L . E j z a k ) , s a n g i o r g i o l 8 1 1 n l . g o v (S. Sangiorgio) Presently at: Joint Research Center, Institute for Reference M a t e r i a l s and Measurements, 2440 Geel - B e l g i u m P r e s e n t l y at: Nikhef, 1098 X G A m s t e r d a m - T h e Netherlands P r e s e n t l y at: L o s A l a m o s N a t i o n a l L a b o r a t o r y , L o s A l a m o s , N M 87545 - U S A P r e s e n t l y at: C E A / Saclay, 91191 G i f - s u r - Y v e t t e - France Deceased Preprint submitted to Astroparticle Physics December
119354119
Entropy of the Stiffest Stars
We analyze the properties of stars whose interior is described by the stiffest equation of state consistent with causality. We note the remarkable fact that the entropy of such stars scales like the area.
125302371
Cosmological SUSY Breaking and the Pyramid Scheme
14559665
A Critique of Pure String Theory: Heterodox Opinions of Diverse Dimensions
I present a point of view about what M Theory is and how it is related to the real world that departs in certain crucial respects from conventional wisdom. I argue against the possibility of a background independent formulation of the theory, or of a Poincare invariant, Supersymmetry violating vacuum state. A fundamental assumption is black hole dominance of high energy physics.Much of this paper is a compilation of things I have said elsewhere. I review a crude argument for the critical exponent connecting the gravitino mass and the cosmological constant, and propose a framework for the finding a quantum theory of de Sitter space.
115478187
Holographic Cosmology and the Arrow of Time
I review the holographic theory of quantum space-time and cosmology, and argue that it may yield insight into the Boltzmann-Penrose question of why the universe began with low entropy. In this model, the observed low entropy initial conditions, maybe the most general initial conditions for cosmology, which avoid collapse into a dense black hole fluid phase.
16630872
Some Thoughts on the Quantum Theory of de Sitter Space
This is a summary of two lectures I gave at the Davis Conference on Cosmic Inflation. I explain why the quantum theory of de Sitter (dS) space should have a finite number of states and explore gross aspects of the hypothetical quantum theory, which can be gleaned from semiclassical considerations. The constraints of a self-consistent measurement theory in such a finite system imply that certain mathematical features of the theory are unmeasurable, and that the theory is consequently mathematically ambiguous. There will be a universality class of mathematical theories all of whose members give the same results for local measurements, within the {\it a priori} constraints on the precision of those measurements, but make different predictions for unmeasurable quantities, such as the behavior of the system on its Poincare recurrence time scale. A toy model of dS quantum mechanics is presented.