Martin A. Pomerantz

Cosmic Rays:Cosmic Rays:

Elementary Particles in NatureElementary Particles in Nature

by Thomas K. Gaisserby Thomas K. Gaisser

ThemesThemes

The atomic view of scienceThe atomic view of scienceCosmic rays & particle physics: 3 examplesCosmic rays & particle physics: 3 examples NeutrinosNeutrinos AntiprotonsAntiprotons Air showersAir showers

Particle astrophysics in AntarcticaParticle astrophysics in Antarctica South Pole Air Shower Experiment (SPASE)South Pole Air Shower Experiment (SPASE) IceCubeIceCube

2400 years of elementary particles2400 years of elementary particles

Democritus c. 460-370 B.C.Democritus c. 460-370 B.C. Atomic theory of matterAtomic theory of matter Not continuous elements (fire, air, Not continuous elements (fire, air,

earth and water) butearth and water) but Indivisible atoms ~ elementary Indivisible atoms ~ elementary

particlesparticles Their interactions, combinations, Their interactions, combinations,

motions explain everythingmotions explain everything

Epicurus c.Epicurus c. 341-271341-271

Lucretius (Rome, c. 99-55)Lucretius (Rome, c. 99-55) de Rerum Natura de Rerum Natura ““least parts” ~ quarksleast parts” ~ quarks

Epicurus

Levels of structureLevels of structureMolecules: combinations of atomsMolecules: combinations of atoms 6CO6CO22 + 6H + 6H22O + light O + light CC66HH1212OO6 6 + 6O+ 6O22

Produce wood (Produce wood (CC66HH1010OO55) by taking carbon out of ) by taking carbon out of

the air and water from the groundthe air and water from the ground

Atoms: compact nucleusAtoms: compact nucleus with electron cloudwith electron cloud p + Mn p + Mn p + e p + e-- + Mn + Mn++ p + Mn + x-ray p + Mn + x-ray electron ejected; recombination x-ray emittedelectron ejected; recombination x-ray emitted

Nuclei: Z protons and (N = A - Z) neutronsNuclei: Z protons and (N = A - Z) neutrons

Nucleons: p = [uud]; n = [udd]Nucleons: p = [uud]; n = [udd]

Epicurean “atom” Minimal parts

Beta-decay and the neutrinoBeta-decay and the neutrino

Nuclear Nuclear --decaydecay A(Z,N) A(Z,N) A(Z+1,N-1) + e A(Z+1,N-1) + e- - + + ee

n n p + e p + e-- + + ee ( n( n = [udd] = [udd] p = [uud] ) p = [uud] )

d d u + e u + e-- + + ee

Neutrino (symbol Neutrino (symbol ) ) hypothesized by Pauli (1930) to conserve energyhypothesized by Pauli (1930) to conserve energy named by Fermi (1933) “little neutral one”named by Fermi (1933) “little neutral one” first detected 1956 (first detected 1956 (ee from nuclear reactor) by from nuclear reactor) by

Cowan and ReinesCowan and Reines 3 neutrino flavors: 3 neutrino flavors: ee, , and and

Elementary Particle PhysicsElementary Particle Physics(a.k.a. High Energy Physics)(a.k.a. High Energy Physics)

Study particles by collisions: p + p Study particles by collisions: p + p ? ?

E = mcE = mc22:: When E >> mcWhen E >> mc22, E , E mass on large scale mass on large scale then ? = many particlesthen ? = many particles

Examples:Examples: p + p p + p p + n + p + n + ++ followed by ( followed by ( ++ ++ )) p + p p + p p + p + p + p (p = antiproton) p + p + p + p (p = antiproton) p + p + 1414N N 200 200 p p + 20 K + …+ 20 K + …

Macroscopic collisionsMacroscopic collisions

+ + + +

P + P P + P + P + P

Warning: This is a flawed analogybecause cars are highlycomposite objects

What are Cosmic Rays?What are Cosmic Rays?

Naturally occurring particles (protons and Naturally occurring particles (protons and nuclei) having very high energiesnuclei) having very high energies

From sources far outside the solar systemFrom sources far outside the solar system

Discovered nearly a century agoDiscovered nearly a century ago

Studied with detectors on balloons and Studied with detectors on balloons and spacecraft as well as from the groundspacecraft as well as from the ground

Positron, pion, kaon were all discovered by Positron, pion, kaon were all discovered by observations of cosmic-ray interactions in observations of cosmic-ray interactions in the atmospherethe atmosphere

-mass and flavor oscillations-mass and flavor oscillations--a recent discovery about particles using interactions of cosmic rays--a recent discovery about particles using interactions of cosmic rays

Cosmic-ray neutrinosCosmic-ray neutrinos p + air p + air + particles + particles + +

e + e + ++ ee

Atmospheric Atmospheric n n anomalyanomaly / / e e 1 (instead of 2) 1 (instead of 2)

upward upward < downward< downward

Explanation: Explanation:

Implies have mass > 0

Artist’s view of Super-K Detector:11,000 20” phototubes viewing 40,000 tonnes (10 million gallons)of water in a mine in Japan

Pictures of Super-KPictures of Super-K

Top left: Super-K half full (1996)Right: unpacking the PMTsBottom: Super-K after accident (Nov. 2001)

Detector is currently being rebuilt

Cherenkov radiation:Cherenkov radiation:signals in Super-Kamiokandesignals in Super-Kamiokande

Sonic boom (from object faster than speed of sound)is analogous to Cherenkov radiation by a charged particle moving faster than speed of light in a medium

Cosmic Gall Cosmic Gall by John Updikeby John Updike

Neutrinos, they are very small.Neutrinos, they are very small. They have no charge and have no massThey have no charge and have no mass And do not interact at all.And do not interact at all. The earth is just a silly ballThe earth is just a silly ball To them, through which they simply pass,To them, through which they simply pass, Like dustmaids through a drafty hallLike dustmaids through a drafty hall Or photons through a sheet of glass.Or photons through a sheet of glass. They snub the most exquisite gas,They snub the most exquisite gas, Ignore the most substantial wall,Ignore the most substantial wall, Cold-shoulder steel and sounding brass,Cold-shoulder steel and sounding brass, Insult the stallion in his stall,Insult the stallion in his stall, And scorning barriers of class,And scorning barriers of class, Infiltrate you and me! Like tallInfiltrate you and me! Like tall And painless guillotines, they fallAnd painless guillotines, they fall Down through our heads into the grass.Down through our heads into the grass. At night, they enter at NepalAt night, they enter at Nepal And pierce the lover and his lassAnd pierce the lover and his lass From underneath the bed - you callFrom underneath the bed - you call It wonderful; I call it crass.It wonderful; I call it crass.

from Telephone Poles and Other Poems by John Updike from Telephone Poles and Other Poems by John Updike © Knopf 1963 © Knopf 1963

Solar NeutrinosSolar Neutrinos

Sudbury Neutrino ObservatoryArt McDonald gave Swann lecture at Bartol/DPA in February

They also oscillate: e [] hardly(Gell-Mann)

little

High-energy acceleratorsHigh-energy accelerators

Accelerator labs Accelerator labs high energy particles high energy particlesCosmic accelerators Cosmic accelerators cosmic rays cosmic rays What are the sources?What are the sources? How are the particles accelerated?How are the particles accelerated? How do they get here?How do they get here? What happens on the way?What happens on the way?

Fermilab’s Tevatron ring is 4 miles around

Particle acceleratorsParticle accelerators

CERN site with LEP tunnel & L3 detector

Cosmic accelerators Cosmic accelerators (some supernova remnants in our galaxy)(some supernova remnants in our galaxy)

SN1987A

SN1054

Circa 1650(Cas-A)

SN1572

Really Big Cosmic accelerators: Really Big Cosmic accelerators: jets in active galaxiesjets in active galaxies

VLA image of Cygnus A

20 TeV gamma rays observed20 TeV gamma rays observedHigher energies obscured by IR lightHigher energies obscured by IR lightbut the universe is transparent to but the universe is transparent to

Primary cosmic-ray antiprotonsPrimary cosmic-ray antiprotonsp + interstellar gas p + interstellar gas p + … p + …

Issues:Issues: Are there exotic sources?Are there exotic sources? Probe the heliosphereProbe the heliosphere

Results: p/p ratioResults: p/p ratio consistent with origin in consistent with origin in

interstellar gasinterstellar gas Predicted change agrees with Predicted change agrees with

Bartol group’s prediction for Bartol group’s prediction for 2000 solar maximum based on 2000 solar maximum based on large-scale structure of solar large-scale structure of solar wind and its magnetic fieldwind and its magnetic field

Interactions at ultra-high energyInteractions at ultra-high energymake air showersmake air showers

Intensity is very lowIntensity is very low ~20 per hour per acre ~20 per hour per acre

for E = 2 million x mcfor E = 2 million x mc22 (~E of biggest accelerator)(~E of biggest accelerator)

~ 1 per sq. km per century ~ 1 per sq. km per century at E = 200 trillion x mcat E = 200 trillion x mc22 (most energetic cosmic ray) (most energetic cosmic ray)

Use large ground arraysUse large ground arrays Several acres …Several acres … Several thousand sq. milesSeveral thousand sq. miles

Schematic view of air shower detection: ground array and Fly’s Eye

Auger detectorAuger detector

Under construction in ArgentinaJim Cronin, Alan Watson, Jim Beatty …

SPASE-AMANDASPASE-AMANDA

SPASE-1, 1987-1997SPASE-1, 1987-1997 Hillas, Pomerantz, WatsonHillas, Pomerantz, Watson (Leeds-Bartol)(Leeds-Bartol)

SPASE-2, 1996 –SPASE-2, 1996 – Current Bartol experimentCurrent Bartol experiment TKG, Watson, Evenson, Stanev, TKG, Watson, Evenson, Stanev,

Tilav, Bai ...Tilav, Bai ... Coincidences with AMANDACoincidences with AMANDA

AMANDA is a neutrino AMANDA is a neutrino telescopetelescope

McMurdoMcMurdo

Amundsen-Scott South Pole StationAmundsen-Scott South Pole Station

Optical Optical sensorsensor

Martin A. Pomerantz Observatory (MAPO)

The IceCube CollaborationThe IceCube CollaborationInstitutions: 11 US and 9 European institutionsInstitutions: 11 US and 9 European institutions (most of them are also AMANDA member institutions)(most of them are also AMANDA member institutions)1.1. Bartol Research Institute, University of DelawareBartol Research Institute, University of Delaware2.2. BUGH Wuppertal, GermanyBUGH Wuppertal, Germany3.3. Universite Libre de Bruxelles, Brussels, BelgiumUniversite Libre de Bruxelles, Brussels, Belgium4.4. CTSPS, Clark-Atlanta University, Atlanta USACTSPS, Clark-Atlanta University, Atlanta USA5.5. DESY-Zeuthen, Zeuthen, GermanyDESY-Zeuthen, Zeuthen, Germany6.6. Institute for Advanced Study, Princeton, USAInstitute for Advanced Study, Princeton, USA7.7. Dept. of Technology, Kalmar University, Kalmar, SwedenDept. of Technology, Kalmar University, Kalmar, Sweden8.8. Lawrence Berkeley National Laboratory, Berkeley, USALawrence Berkeley National Laboratory, Berkeley, USA9.9. Department of Physics, Southern University and A\&M College, Baton Rouge, LA, USADepartment of Physics, Southern University and A\&M College, Baton Rouge, LA, USA10.10. Dept. of Physics, UC Berkeley, USA Dept. of Physics, UC Berkeley, USA 11.11. Institute of Physics, University of Mainz, Mainz, GermanyInstitute of Physics, University of Mainz, Mainz, Germany12.12. Dept. of Physics, University of Maryland, USADept. of Physics, University of Maryland, USA13.13. University of Mons-Hainaut, Mons, BelgiumUniversity of Mons-Hainaut, Mons, Belgium14.14. Dept. of Physics and Astronomy, University of Pennsylvania, Philadelphia, USADept. of Physics and Astronomy, University of Pennsylvania, Philadelphia, USA15.15. Dept. of Astronomy, Dept. of Physics, SSEC, PSL, University of Wisconsin, Madison, USADept. of Astronomy, Dept. of Physics, SSEC, PSL, University of Wisconsin, Madison, USA16.16. Physics Department, University of Wisconsin, River Falls, USAPhysics Department, University of Wisconsin, River Falls, USA17.17. Division of High Energy Physics, Uppsala University, Uppsala, SwedenDivision of High Energy Physics, Uppsala University, Uppsala, Sweden18.18. Fysikum, Stockholm University, Stockholm, SwedenFysikum, Stockholm University, Stockholm, Sweden19.19. University of Alabama, Tuscelosa, USAUniversity of Alabama, Tuscelosa, USA20.20. Vrije Universiteit Brussel, Brussel, BelgiumVrije Universiteit Brussel, Brussel, Belgium

IceCubeIceCube

1400 m

2400 m

AMANDA

South Pole

IceTop

Skiway80 Strings80 Strings4800 PMT 4800 PMT Instrumented volume: 1 Instrumented volume: 1 km3 (1 Gt)km3 (1 Gt)IceCube is designed to IceCube is designed to detect neutrinos of all detect neutrinos of all flavors at energies from flavors at energies from 101077 eV (SN) to 10 eV (SN) to 102020 eV eVMotivation: weakly Motivation: weakly interacting interacting nn can can emerge from deep emerge from deep inside a sourceinside a sourceNeed BIG detectorNeed BIG detector

Eµ= 10 TeVEµ= 6 PeV

Muon EventsMuon Events

Measure energy by counting the number of fired PMT.Measure energy by counting the number of fired PMT. (This is a very simple but robust method)(This is a very simple but robust method)

Future prospectsFuture prospects

The IceCube neutrino telescope--goals:The IceCube neutrino telescope--goals: Find high-energy neutrinos: unique probes of Find high-energy neutrinos: unique probes of

cosmic accelerators--see brochurescosmic accelerators--see brochures Measure primary cosmic rays to > billion mcMeasure primary cosmic rays to > billion mc2 2

with a three-dimensional air shower detectorwith a three-dimensional air shower detector

A multi-year project (10-15 years)A multi-year project (10-15 years) Many high-level reviews passedMany high-level reviews passed First year funding in NSF plan for current yearFirst year funding in NSF plan for current year We are working hard to make this happenWe are working hard to make this happen

South Pole Air Shower ExperimentSouth Pole Air Shower Experiment

Sunset, March 21, Sunset, March 21, 20022002

Photo of electronics Photo of electronics tower by Katherine tower by Katherine RawlinsRawlins

Cosmic rays in AntarcticaCosmic rays in Antarctica

May 2001 Awards May 2001 Awards Day at which Martin Day at which Martin Pomerantz received Pomerantz received an honorary degree an honorary degree from UDfrom UD

Fission, fusion and neutrinosFission, fusion and neutrinos

Example of nuclear fissionExample of nuclear fission nn + U + U235 235 Xe Xe140140 + Sr + Sr9292 + 3n + 3n nn + U + U235 235 … … daughter nuclei multi-daughter nuclei multi--decay -decay multi- multi- ee

1956: Cowan & Reines detect 1956: Cowan & Reines detect ee at reactorat reactor

Nuclear fusion (e.g. in the Sun)Nuclear fusion (e.g. in the Sun) p + p p + p 22H + H + ee (neutrino, not anti-neutrino ) (neutrino, not anti-neutrino ) 22H + p H + p 33He + He + 33He + He + 33He He 44He + 2pHe + 2p 2002 SNO experiment solves solar 2002 SNO experiment solves solar problemproblem