14/02/19

1

HighEnergy(Multimessenger)AstroparticlePhysics

2018/19

AlessandroDeAngelisUniv.UD/PD,INFN/INAFPadova&LIP/ISTLisboa

1.Introduction

Aboutthiscourse

2

•  10lecturesfromFeb12toFeb28•  Include2“handson”sessiononanalysis

ofexperimentaldatafromtheFermisatellite

•  Whatyouwilllearn:–  Cosmicraysanddetectors–  Fermiaccelerationmechanism–  Thesourcesofcosmicrays–  TeV-PeVgamma-rayastrophysics–  Neutrinoastrophysics–  TheDarkMatterproblem–  Gravitationalwaves,neutrinos&

multiwavelengthastrophysics–  Openproblems;thefuture–  AnalyzedatafromFermi

•  Howyouwillbeevaluated:–  Seminar/analysis,topicofyourchoice

(Youcandownloaditforfreefromthewebpageofthecourse)

14/02/19

2

Syllabu

s201

8/19

3

Introducingmyself…•  ProfessorofphysicsattheUniversitiesofUdine,PadovaandLisbon,Iworkinhigh-energyastrophysics(Iam

thePIoftheASTROGAMconceptsatellite:ASTROGAM,e-ASTROGAM,AS-ASTROGAM…,lookintheweb)

•  Maininterests:HEparticleastrophysics(inparticularwithgammarays)andfundamentalphysicswithaccelerators

•  GraduatedinPadova(bubblechamberphysics),post-doc(calibrationandcommissioningofacalorimeter)andthenresearchassociateandstaffmemberatCERN(1993-1999)–  ConvenoroftheQCDgroupandresponsibleofthesoftwareforphysicsanalysisoftheDELPHIexperimentatLEP.Wrote

thefirstHEPpaperusingartificialNeuralNetworks

•  ComebacktoItalyin1999,movingtogamma-rayastroparticlephysics(simulation,software,physicsanalysis)–  GLASTsatellite(akaFermi),fromNASA

–  MAGICtelescope,inCanaryIslands.Projectscientistfrom2005to2007andin2010.

–  CherenkovTelescopeArray

–  ASTROGAMsatellitesince2016

•  Authororco-authorofmorethan600scientificpublications,andthreebooks(oneofpopularization:L’enigmadeiraggicosmici,Springer).

•  Courseslecturedduringtherecentyears:ElectricityandMagnetism,QuantumPhysics,QuantumChromoDynamics,AstroparticlePhysics,ParticlePhysics

4

14/02/19

3

AnobservatoryforgammaraysIntheMeV/GeVdomain

http://eastrogam.iaps.inaf.it

https://arxiv.org/abs/1611.02232(Exp.Astronomy17)

6

14/02/19

4

Thelast10yearshavebeenthegoldenyearsofexperimentalveryhighenergyastrophysics

•  2003-2010:Hypernovaeproducelonggamma-raybursts(GRBs)•  2007-2017:Cosmicraysbeyond8EeVcomefromAGN(theregionof

accretionofSMBHingalaxies)•  2007-2017:Cosmicraysfrom100TeVto1PeVcomefromsupernova

remnants•  2013:Astrophysicalneutrinosabove100TeVcomefromextragalactic

sources,probablyAGN.Lessthan5%comefromGRBs•  2015:Gravitationalwave(GW)emissionaccompaniesBH-BHmergings,and

therearequitealotofthem•  2017:NS-NSmergersproduceGWandshortGRBs(upto~MeV)•  2018:Flaringblazarproducesimultaneousneutrinoandgamma-ray

emissions)

FiveNobelPrizes(2002,2006,2011,2015and2017)toastroparticlephysicsinthenewmillennium

7

AlookattheUniversearoundus(homogeneity?)

8

•  TheMilkyWayisaspiralgalaxysome100000light-years(ly)across,1000lyto2000lythick,withtheSolarSystemlocatedwithinthedisk,about30000lyawayfromtheGalacticCenter,intheOrionarm.–  Thestarsintheinner10000lyformabulge.TheGChoststhesupermassiveBHSgrA*ofsome4million

solarmasses,asdeterminedbystudyingtheorbitsofnearbystars.–  Theinterstellarmedium(ISM)isfilledbypartlyionizedgas,dustandcosmicraysanditaccountsforsome

15%ofthetotalmassofthedisk.–  AmagneticfieldofafewGinteractswiththeISM.

•  Withits1011stars,theMilkyWayisrelativelylarge.Teamingupwiththesimilar-sizedAndromedagalaxy,ithasgravitationallytrappedmanysmallergalaxies:together,theyallconstitutetheso-calledLocalGroup–  morethan50galaxies,includingnumerousdwarfgalaxies-somearejustsphericalcollectionsofhundreds

ofstarsthatarecalledglobularclusters–  TheLocalGroupcoversadiameterof10Mly(i.e.,3.1Mpc);ithasatotalmassofabout1012solar

masses.–  Supergroups(superclusters)canspanupto~50Mly)

Cosmologicalprinciple?

14/02/19

5

TheUniverseisexpanding

9

•  In1929Hubble,studyingtheemissionofradiationfromgalaxies,comparedtheirspeed(calculatedfromtheDopplershiftoftheiremissionlines)withdistance,anddiscoveredthat

v=H0dH0~70km/s/Mpc~1/14Gyr

•  Galaxiesareobservedtomoveawayatspeedsproportionallyhigherforlargerdistances.TheHubbleconstantdescribestherateofincreaseofrecessionvelocitiesforincreasingdistance.TheDopplerredshift

z=Δλ/λ

canthusalsobeusedasametricofthedistanceofobjects

•  AsimpleinterpretationoftheHubblelawisthat,iftheUniversehadalwaysbeenexpandingataconstantrate,about14billionyearsagoitsvolumewaszero-naively,wecanthinkthatitexplodedthroughaquantumsingularity,suchanexplosionbeingusuallycalledthe“BigBang.”ThisageisconsistentwithpresentestimatesoftheageoftheUniversewithingravitationaltheoriesandslightlylargerthantheageoftheoldeststars,whichcanbemeasuredfromthepresenceofheavynuclei.Thepicturelooksconsistent.

•  TheadiabaticexpansionoftheUniverseentailsafreezingwithexpansion,whichinthenowadaysquietUniversecanbesummarizedasalawfortheevolutionofthetemperatureTonthesize T=b/RThepresenttemperatureis~2.7K,andcanbemeasuredfromthespectrumoftheblackbodyradiation(theso-calledcosmicmicrowavebackground,orCMB,permeatingtheUniverse).

Stars

10

•  Starsalsoformedbygravitationalinstabilities.Cloudsofgasformedafterprimordialnucleosynthesis(mostlyHandHe)collapseand,iftheirmassissuitable,eventuallyformstars.

•  Stellarmassesarelimitedbytheconditionsthat(i)nuclearreactionscanswitchoninthestellarcore(>0.1solarmasses),and(ii)theradiationdragoftheproducedluminosityontheplasmadoesnotdisruptthestar’sstructure(<100solarmasses).

•  ForastarliketheSun,formationtakes~50Myr;thetotallifetimeis~11Gyrbeforecollapsingtoawhitedwarf,andinthecaseofourSunsome4.5billionyearsarealreadygone.

•  Thefateofastardependsonitsmass.Theheavierthestar,thelargeritsgravitationalenergy,andthemoreeffectivearethenuclearprocessespoweringit.Theouterlayersaresupportedagainstgravityuntilthestellarcorestopsproducingfusionenergy;thenthestar

•  Main-sequencestarsover8solarmassescandieinaveryenergeticexplosioncalleda(core-collapse,orTypeII)supernova.Thestar'score,madeofiron(massdefectpernucleonismaximum)collapsesandthereleasedgravitationalenergy(~1046J)goesasheatingtheoverlyingmass

•  Elements:(H,He),CNO,Si,Fe•  Theheavierthestar,themoreeffectivethefusionprocess,

andtheshorterthelifetime.

14/02/19

6

Expansion,composition,fateoftheUniverse

11

ForaflatUniverse

•  ThestudyofstellarmotionsingalaxiesindicatesthepresenceofalargeamountofunseenmassintheUniverse.Thismassseemstobeofakindpresentlyunknowntous;itneitheremitsnorabsorbselectromagneticradiation(includingvisiblelight)atanysignicantlevel.Wecallitdarkmatter:itsabundanceamountstoanorderofmagnitudemorethantheconventionalmatterwearemadeof.

•  Darkmatterrepresentsoneofthegreatestcurrentmysteriesofastroparticlephysics.Indicationsexistalsoofafurtherformofenergy,whichwecalldarkenergy.

•  Weliveinaworldmostlyunknown.TheevolutionoftheUniverseandoureverydaylifedependonthisunknownexternalworld.–  TheultimatedestinyoftheUniverse,aperpetualexpansionora

recollapse,dependsonitsenergydensity–  Moreover,everysecond,high-energyparticles(above1GeV)of

extraterrestrialoriginpassthrougheachsquarecentimeterontheEarth,andtheyaremessengersfromregionswherehighlyenergeticphenomenatakeplace.Thesearethecosmicrays

–  ItisnaturaltotrytousethesemessengersinordertoobtaininformationonthehighestenergyeventsoccurringintheUniverse,andonitscomposition.

~5GeV/m3

ShortphenomenologyofCosmicRays

•  Cosmicrays(CR)aresubatomicparticlesreachingtheEarthfromoutside

•  Theyaremostlyprotons–  Buttheminority(heavynuclei,neutrinos,gammas,antimatter…isveryimportant)

•  Thefluxdependsstronglyonenergy–  Theyreachthehighestenergies,upto1021eV

12

Knee

Ankle

LHC:1beam LHC:2beams

Mostly

from

theSun

Mostly

galactic

Extragalactic?

14/02/19

7

•  Kineticenergyislikelytocomefrompotentialgravitationalenergy(collapsesofastrophysicalobjects)–  Below~107GeV:likelytobeGalactic

(supernovaremnants)–  Above:likelytobeextragalactic(accreting

supermassiveblackholes:ActiveGalacticNuclei)

•  OnceCRhittheatmosphere,theyareabsorbedgeneratingshowersofparticles

13

14

Fermi,Egret

Magic,Veritas

IC443

W51:gammarayscomefromamolecularcloudseparatedfromthepulsar

14/02/19

8

CosmicRaysonMars

“…vi fu più di uno che mostrò incredulità. Ma l’odio rende caliginoso l’intelletto… e se costoro avessero visto gli elogi che PadreKircher ha ricevuto e le testimonianze sulla sua capacità di ricostruire i frammentidell’Obelisco Panfilio, non avrebbero il coraggio di aprire bocca…”

G. Petrucci, 1666

Professore Ordinario di Astronomia e Astrofisicaall’Università di Roma “Tor Vergata”, RobertoBuonanno è stato direttore dell’OsservatorioAstronomico di Roma fino al 2005 e membro delVisiting Committee dell’ESO, European SouthernObservatory. Attualmente è Presidente della SocietàAstronomica Italiana e Senior Astronomer pressol’ASDC, ASI Data Center. In questa stessa collana ha già pubblicato Il cielo sopra Roma.

› springer.com

ISBN: 978-88-470-1497-8

123

In The Mercury 13 la Ackmann porta alla luce unepisodio sconosciuto, avvincente e mozzafiato dellastoria dell'astronautica, nonché della storiadell'emancipazione femminile e, più in generale,della storia del genere umano. A cavallo del 1960,tredici donne pilota americane hanno sostenuto esuperato brillantemente gli stessi test a cui venivanosottoposti gli astronauti (maschi) americani.Purtroppo i tempi non erano maturi, le donne eranoancora tenute essenzialmente a fare le "moglidell'astronauta", e la Luna è rimasta un sogno pertutte loro.

1

ACKMANN

MER

CUR

Y 13

pagine di scienza

Alessandro De Angelis

L’enigma dei raggi cosmici

Le più grandi energie dell’universo

Buttheyarealsoattheoriginoflife:

Carbonhasextraterrestrial

origin

TheCH3sequenceisactivatedbycosmicrays

14/02/19

9

Howdidwelearnallthis?(historyofa100-yearsinvestigation)

(F.Capra/W.Disneyproduction,a1957moviewrittenbyAnderson&Rossi)

Electroscopesdischargespontaneously.Why?

•  1785:Coulombfoundthatelectroscopescanspontaneouslydischargebytheactionoftheairandnotbydefectiveinsulation

•  1835:FaradayconfirmstheobservationbyCoulomb,withbetterinsulationtechnology

•  1879:Crookesmeasuresthatthespeedofdischargeofanelectroscopedecreasedwhenpressurewasreduced(conclusion:directagentistheionizedair)

18

14/02/19

10

100yearslater:causemightberadioactivity

•  1896:spontaneousradioactivitydiscoveredbyBecquerel

•  1898:Marie(31)&PierreCuriediscoverthatthePoloniumandRadiumundergotransmutationsgeneratingradioactivity(radioactivedecays)–  Nobelprizeforthediscoveryofthe

radioactiveelementsRadiumandPolonium:the2ndNobelprizetoM.Curie,in1911

–  Inthepresenceofaradioactivematerial,achargedelectroscopepromptlydischarges

–  Someelementsareabletoemitchargedparticles,thatinturncancausethedischargeoftheelectroscopes.

–  Thedischargerateofanelectroscopewasthenusedtogaugethelevelofradioactivity

19

Dischargeofanelectroscopebyaradioactivematerial(Duncan1902)

20

14/02/19

11

Wheredoesnaturalradioactivitycomefrom?

•  Forsureinpartfromthesoil•  ForsureinpartfromtheSun•  Fromtheatmosphere?•  Isthisthefullstory?

•  Inthebeginning,thedominantopinionwasthat(almost)allthehighenergyradiationwascomingfromthesoil

21

TheexperimentsatthebeginningoftheXXcentury•  1900:WilsonandElster&Geitelimprove

thetechniqueforacarefulinsulationofelectroscopesinaclosedvessel,improvingthesensitivity

•  1901:Wilsonmakestheproposalofanextraterrestrialorigin.Hismeasurementsintunnelshowevershownoreductioninionization

22

1903-06:Rutherford&CookeandMcLennan&Burtonshowthationizationismarginallyreducedwhenanelectroscopeissurroundedbymetalshields.McL&Bputalsotheelectroscopeinabox,andtheyfillitwithwater.Machecomparesthevariationsoftheradioactivitywhentheelectroscopeissurroundedbyshieldsofmetalwiththediurnalvariations;nosignificantreduction

(Elster,Geitel)

(C.T.R.Wilson)

14/02/19

12

•  In1901NikolaTeslapatented(USpatent#685,957/8)an“ApparatusfortheUtilizationofRadiantEnergy”TheseradiationsaregenerallyconsideredtobeethervibrationsofextremelysmallwaveIengths[…]Thisphenomenon,Ibelieve,isbestexplainedasfollows:thesunaswellasothersourcesofradiantenergythrowoffminuteparticlesofmatterpositivelyelectrified,which[…]communicateanelectricalcharge

1particle/cm2/s<E>~3GeV

•  Coulditwork?Yes

•  HowmuchpowercanitgenerateP<3GeVx10000CR/sm2⇒ P<5µW/m2

(Solarenergy:~1000W/m2) 23

TheexperimentsinthebeginningoftheXXcentury•  1907:Strongstudiesradioactivityinavarietyofplaces

including(1)hislab(2)thecenterofacisternfilledwithrainwaterand(3)theopenair;resultsdominatedbystatistical&systematicerrors

•  1907-08:EvemakesmeasurementsovertheAtlanticOcean,whichindicateasmuchradioactivityoverthecentreoftheoceanashehadobservedinEnglandandinMontreal.Hemakesalsosystematicmeasurements,laterusedbyWulf,Pacini,Hess

•  1908:Elster&Geitelobserveafallof28%whentheapparatusistakenfromthesurfacedowntothebottomofasaltmine.Theyconcludethat,inagreementwiththeliterature,theEarthisthesourceofthepenetratingradiationandthatcertainwaters,soilsandsaltdeposits,arecomparativelyfreefromradioactivesubstances,andcanthereforeactasefficientscreens

24

(Eve,Rutherford)

14/02/19

13

Inparallel,thecloudchamber…

Wilsonobtainedthefirstimagesofthetracksofαandβparticles.AsBlackettremarked,‘[Themanyexquisitephotographs…]stillremainamongthetechnicallybestphotographsevermade.’

‘themostoriginalandwonderfulinstrumentinscientifichistory’(Rutherford)

FatherWulf:atrueexperimentalist

•  TheodorWulf,GermanJesuit,professorinHollandandinRome,perfectedtheelectroscopein1908-09,uptoasensitivityof1volt(andmakingittransportable)

26

14/02/19

14

TheWulfexperiments(1909-1910)

•  WulfhadtheideaifmeasuringradioactivityontopoftheEiffeltower(~300m)andcomparetoground,atdayandnight

–  Thedecisivemeasurement:WulfwasonaEasterholidaytriptoParisandbroughtafewelectroscopeswithhim

•  Ifmostoftheradioactivitywascomingfromthesoil,anexponentialdecreasee-h/λ wasexpected

•  Resultswerenotconclusive

–  Note:atthattimepeoplewereconvincedthatnaturalradioactivitywasmostlyduetogammarays

•  Takenasaconfirmationofthedominantopinion:radioactivitycamefromthesoil

27

DomenicoPacini’sbreak-through•  DomenicoPacini(1878-1934),meteorologistin

RomaandthenprofessorinBari,makesmeasurementsin1907-1911,firstcomparingtherateofionizationonmountainsatdifferentaltitudes,overalake,andoverthesea–  Comparingmeasurementsonthegroundandonaseaa

fewkmoffthecoastinLivorno,a30%reductionofradioactivity

–  Ahintthatthesoilisnot(theonly)responsibleofradiation:inthehypothesisthattheoriginofpenetratingradiationsisonlyinthesoil…itisnotpossibletoexplaintheresultsobtained(Pacini1910;quotedbyHess)

28

•  InJune1911,thewinningidea:immersinganelectroscope3mdeepinthesea(atLivornoandlaterinBracciano)Pacini,33-y-old,findsasignificant(20%at4.3σ)reductionoftheradioactivity

14/02/19

15

Paciniconcludesthat“asizablecauseofionizationexistsintheatmosphere,originatingfrompenetratingradiation,independentofthedirectactionofradioactivesubstancesintheground.”

Pacini’sexperimentmarkedthebeginningoftheunderwatertechniqueforCRstudies

“Theexplanationappearstobe,duetotheabsorbingpowerofwaterandtheminimumamountofradioactivesubstancesinthesea,thatradiationcomingfromtheoutsideisabsorbedwhentheapparatusisimmersed.(NuovoCim.,February1912)”

29

Pacini’sinstrumentsA.DeAngelis 30

14/02/19

16

RemakeofthePaciniexperimentin2011

(G.Batignanietal.,GiornalediFisica,Sept.2011)

31

Balloonexperiments:Gockel

•  HowtoincreasethesensitivityofWulf’smeasurementsontheEiffeltower?Flyingonballoons!

•  Thefirstballoonflightswiththepurposeofstudyingthepropertiesofpenetratingradiationwerearrangedin1909,inGermanybyBergwitz,andinSwitzerlandbyA.Gockel,professorattheUniversityofFribourg

•  Ascendingupto4000m,Gockelfoundthattheionizationdidnotdecreasewithheightasexpectedonthehypothesisofaterrestrialorigin–  Copyrightoftheterm“kosmische

Strahlung” 32

Note:GayLussacandBiotflewto6400min1804tostudypropertiesofairatdifferentp,T.RobertsonandLhoesthadreachednearly7000mina5hflightfromHamburgtoHannoverin1803,tomeasureB

Altitude(km)

20

10

1 2

Ionpairs/(cm

3 s)

3

14/02/19

17

Anewboost:Hess •  TheAustrianVictorHess(1883-1964),atthattimeworkinginWienandinGraz,startedstudyingWulf'selectroscope,andmeasuringcarefullytheabsorptioncoefficientsofradioactivityinair

–  Thoroughcheck&improvementofEve’swork;separationbetweenalpha,beta,gamma

•  In1911,hecontinuedhisstudieswithballoonobservations:hemade2ascensionsat~1300m,measuringpossiblevariationsofradioactivity,andfoundnoeffect.Hehad3WulfelectroscopesinZnboxesofdifferentthicknesses

33

(Wien1907)

!"#$%&'()*+,(

-./(012345)6+

7 4,(

!"#$%&'()*+,(

891+:'3(;(

891+:'3(<(

<=<7(

7>(

;>(

<>(

?>(

@>(

A>(

;>(

;( @( A( ;( @( A( ?(

<=<@(-./(012345)6+

7 4,(

Hess’finalballoonflights

•  FromApril1912toAugust1912Hesshadtheopportunitytofly7times.Inthefinalflight,onAugust7,Hess,29-y-old,reached5200m–  Hisresultsshowedthattheionization,afterpassingaminimum,increasedconsiderablywithheight

–  Heconcludedthattheincreaseoftheionizationwithheightisduetoaradiationcomingfromabove,andthoughtthatthisradiationhadextra-terrestrialorigin

34

14/02/19

18

RemakeofHess’experimentin2012

35A.DeAngelis

Kolhörsterandthefinalconfirmation

!"#$%&'()*+,(

-./(012345)6+

7 4,(

!"#$%&'()*+,(

891+:'3(;(

891+:'3(<(

<=<7(

7>(

;>(

<>(

?>(

@>(

A>(

;>(

;( @( A( ;( @( A( ?(

<=<@(-./(012345)6+

7 4,(

•  TheresultsbyHesswerelaterconfirmedbythe26-y-oldKolhörsterinanumberofflightsupto9200m

–  Anincreaseoftheionizationupto10xatsealevelfound

•  Theabsorptioncoefficientoftheradiationfromtopwasalsoestimated,andturnedouttobe8timessmallerthantheabsorptioncoefficientofairforgammaraysasknownatthetime

–  Thisresultwasneglectedbythewriterandbythereaders!

36

ThefinalflightbyKolhörsterwouldbeperformedon28June1914,thesamedayoftheassassinationofArchdukeFranzFerdinandofAustriaontheromanbridgeofSarajevo:WWIstarts

14/02/19

19

WordWarIwasheseverythingout…andsciencerestartsinthenewworld

•  DuringWWIandimmediatelyafter,fewinvestigationswereperformed.Kolhörsterimprovedhisapparatusandmademeasurementsin1923inagreementwithearlierballoonflights

•  Therewere,however,alsonegativeattitudesagainstextraterrestrialradiation.Hoffmann(1924),andBehounek(1925),usingnewlydevelopedelectrometers,concludedthationizationwasduetoradioactiveelementsintheatmosphere

•  Afterthewar,thefocusoftheresearchmovedtotheUS;Millikan&Bowendevelopedalowmass(200g)electrometerandionchamberforunmannedballoonflightsusingdatatransmissiontechnologydevelopedduringthewar

–  Inflightsupto15000minTexastheyfoundaradiationintensity¼theintensityreportedbyHessandKolhörster.Theyattributedthisdifferencetoaturnoverintheintensityathigheraltitude,beingunawarethata(latitude)geomagneticeffectexisted

–  Millikanconcludedthattherewasnoextraterrestrialradiation:hisstatementattheAmericanPhysicalSocietyin1925was“Thewholeofthepenetratingradiationisoflocalorigin".Millikanwasstronglyattacked,e.g.,byCompton.

37

Truthreestablished(butmeritstolen)

•  In1926,however,MillikanandCameroncarriedoutabsorptionmeasurementsoftheradiationatvariousdepthsinlakesathighaltitudes–  TheyreproducedPacini’sdepth

effect,andtheyconcludedthattheseparticlesshootthroughspaceequallyinalldirections,callingthem“cosmicrays”

–  IntheconclusivePhys.Rev.article,theyignoredWulf,Gockel,Pacini,Hess

•  Millikanwashandlingwithenergyandskillthecommunicationwithmedia,andintheUSthediscoveryofcosmicraysbecame,accordingtothepublicopinion,asuccessofAmericanscience–  Millikanarguedthatthecosmic

rayswerethe“birthcriesofatoms”inourgalaxy 38

14/02/19

20

Marketingcosmicrays

39

•  Anyway,alsoHessandKolhörsterwerenotreferenced(Gockel,whosemeasurementhadnotsucceeded,was).Bergwitz,HessandKolhörsterwroteanarticleemphasizingtheirpriorityontheballoonresults(Phys.Zeit.1926). 40

[…]

14/02/19

21

Chargedorneutral?•  Itwasgenerallybelievedthatthecosmicradiationwasgammabecauseofitspenetratingpower(thepenetratingpowerofrelativisticchargedparticleswasnotknown)–  Millikanhadputforwardthe

hypothesisthatthegammarayswereproducedwhenprotonsandelectronsformHenucleiininterstellarspace

•  ThegeomagneticeffectinCR(theCRfluxdependsonlatitude)wasdiscoveredaccidentallyin1927bytheDutchresearcherJ.Clay–  ClaywasmeasuringradiationinJava;

in1927hecarriedhisdetectorinatripfromJavatoGenova

•  ConfirmedbyClayhimselfin1928(JavatoAmsterdam),byKolhörster,byRossi,byCompton+

41

42

14/02/19

22

Inthemeantime(late‘20s),Geigercountersenterthegame

•  Easiermeasurement•  Fastresponse(possibilityofbuildingcoincidences)

43

(HansGeigerin1928)

BeppoOcchialini:“theGeiger-MullercounterwasliketheColtintheFarWest:acheapinstrumentusablebyeveryoneonone'swaythroughahardfrontier.”

ArthurComptonorganizedaworldwidesurveyofthedependenceofcosmicintensityongeomagneticlatitude.

44

14/02/19

23

45

46

14/02/19

24

AdramaticresultbyBrunoRossi(withHeisenberg!)

47

Positiveornegative?TheEast-Westeffect•  1933-34:threeindependent

experiments(Alvarez&Compton,Johnson,Rossi)findthattheintensityofCRisgreaterfromtheWestthanfromtheEast=>mostprimarycosmicraysarepositivelychargedparticles–  InthecourseofhisEast-Westexperiment,Rossi(28yrold)inEritreadiscoverscosmic-rayairshowers,butdoesnotstudythemindetail

•  PublicationinItalian,again…

•  Augerwillre-discoverandstudyinlargerdetailin1936

48

B

14/02/19

25

Rossi’sarticle(1932)

49

Rossi,LaRic.Sc.Suppl.1(1934)579

Discoveryofextensiveairshowers.

50

14/02/19

26

AconjectureontheoriginofCR•  Ina1931lecturecourseatCaltech,Zwicky

introducedtheterm“super-nova”todistinguishtheexplosionofanentirestarfromthelesspowerfulnova,whichinvolvedviolentandrepeatedoutburstsonthesurfaceofanunstablestar

•  ZwickyteamedupwiththeGerman-AmericanastronomerWalterBaadetoworkonthesupernovaidea.Atascientificconferencein1933,theyadvancedthreeboldnewideas:1.  massivestarsendtheirlivesinexplosionswhich

blowthemapart2.  suchexplosionsproducecosmicrays3.  theyleavebehindacollapsedstarmadeof

densely-packedneutrons51

(Zwickyin1930)

Mostdiscoveriesinelementaryparticlephysicsintheearlyyearsduetocosmicrays

•  Thankstothedevelopmentofcosmicrayphysics,scientistsknewthenthatastrophysicalsourceswereprovidingvery-highenergybulletsenteringtheatmosphere

•  Itwasthenobvioustoinvestigatethenatureofsuchbullets,andtousethemasprobestoinvestigatematterindetail,alongthelinesoftheexperimentmadebyRutherfordin1900–  ImportantcontributionsbyW.Heisenberginthisphase

•  Particlephysics,thescienceofthefundamentalconstituentsofmatter,startedwithcosmicrays.Manyfundamentaldiscoveriesweremade…

52

14/02/19

27

Antimatter(theantielectron,orpositron:

Anderson1933)

•  PicturetakenbyAndersonin1932ofacloudchamber(NobeltoWilsonin1927)inthepresenceofamagneticfield

•  ThebandacrossthemiddleisaPbplate,whichslowsdowntheparticles.Themomentumofthetrackaftercrossingtheplateissmallerthanbefore

•  Fromthedirectioninwhichthepathcurvesonecandeducethattheparticleispositivelycharged

•  Masscanbededucedfromthelongrangeofthetrack-aprotonwouldhavecometorestinashorterdistance

=>Itisapositiveelectron!

Atthesametime,gamma->e+e-(Occhialini&Blackett)

•  ConsistentwithWeil’sinterpretationofDirac’sequation(1927-28)…

53

ButalsoSkobelzyn1927Powell1928…?

e+

Anote:Dirac’sequationannouncedin‘28inCambridge;atthesameconferenceSkobelzynspokeaboutsomeunexplainable“wrongcharge”events.

1936:TheNobelprizetoHess(&Anderson)Hesswasawardedthe1936NobelPrizeinphysics,sharedwithAnderson.HesswasnominatedbyClay,Compton:–  Thetimehasnowarrived,itseemsto

me,whenwecansaythattheso-calledcosmicrayshavetheiroriginatremotedistancesfromtheEarth[…]andthattheuseoftherayshasbynowledtoresultsofsuchimportancethattheymaybeconsideredadiscoveryofthefirstmagnitude.[...]Itis,Ibelieve,correcttosaythatHesswasthefirsttoestablishtheincreaseoftheionizationobservedinelectroscopeswithincreasingaltitude;andhewascertainlythefirsttoascribewithconfidencethisincreasedionizationtoradiationcomingfromoutsidetheEarth 54

14/02/19

28

Later,manynewdiscoveriesinfundamentalphysicsfromcosmicrays

•  1937:Themuon,ormulepton,discoveredbyNeddermeyer+(mistakenforthepionuntil1947:Conversi,Pancini,Piccioni)

•  1947:Pion(orπmeson),thefirstmeson,discoveredbyLattes,Occhialini&Powell(predictedbyYukawain1935)

•  1947:Kaon(orKmeson),thefirststrangeparticle,discoveredbyRochester&Butler

•  1951:Λ,thefirststrangebaryon,discoveredbyArmenteros+

•  1951-54:Parityviolation(G-stack,thefirstEuropeancollaboration–motherofthemodernHEPcollaborations)

•  CRphysicsisrelativelycheap,whichisimportantinthepost-warconditionsofEuropeanscience(mountain-toplabs,balloons…)

55

ParticlesfoundincosmicraysPositronMuonsChargedPionsKmesonsLambdaSigmaXi

56

14/02/19

29

…andnewhintsforunderstanding(Fermi1949)

•  Proposalof2ndorderacceleration(Fermi,PR,1949)

57

Andalso:themaximumpossibleenergyforaterrestrialacceleratoris~5000TeV(1954)

Fermi’s2ndordertheoryforaccelerationofcosmicrays

58

14/02/19

30

OrganizedbyLouisLeprince-RinguetandPatrickBlackett 59

The1953CRCatBagneresdeBigorre(Cronin2011,arXiv:111.5338)

•  FromtheconcludingremarksbyLeprince-Ringuet:

“Ifwewanttodrawcertainlessonsfromthiscongresslet’spointoutfirstthatinthefuturewemustusetheparticleaccelerators.Let’spointoutforexamplethepossibilitythattheywillpermitthemeasurementofcertainfundamentalcurves(scattering,ionization,range)whichwillpermitustodierentiateeffectssuchastheexistenceofpimesonsamongthesecondariesofKmesons.

Iwouldliketofinishwithsomewordsonasubjectthatisdeartomyheartandisequallysotoallthe“cosmicians",inparticularthe“oldtimers".[…]Wehavetofacethegravequestion:whatisthefutureofcosmicrays?Shouldwecontinuetostruggleforafewnewresultsorwoulditbebettertoturntothemachines?

Onecannodoubtsaythatthatthefutureofcosmicradiationinthedomainofnuclearphysicsdependsonthemachines[…].Butprobablythispointofviewshouldbetemperedbythefactthatwehavetheuniquenessofsomephenomena,quiterareitistrue,forwhichtheenergiesaremuchlarger[…]”

•  Thentheacceleratorerastarts…Andaparticlezoo…60

14/02/19

31

(…)

1953:researchoncosmicraysisinCERN’s

constitution

LegacyfromG-stack

TheOrganizationshall(…)confineitsactivitiesto(…)theconstructionandoperationofoneormoreinternationallaboratoriesforresearchonhigh-energyparticles,includingworkinthefieldofcosmicrays

62

14/02/19

32

Theflamestillburnsinthefollowingyears

•  CMB(1964)•  X-rayastrophysics

–  Rockets(1962)andsatellites(Uhuru1970,…)•  VHEgamma-rayastrophysics

–  Manyattemptsin‘60-’70;observationofCrababove100GeV,Weekesetal.1989–  Presentlarge-scaleIACTsHESS,MAGIC,VERITASèCTA;Agile,Fermisatellites

•  EHEcosmicdetectors–  Observationofaparticle~1020eVin1962atVolcanoRanch(Linsley,Scarsietal.

1962)–  1966:theGZKlimit–  …–  Presentlarge-scaledetectors:thePierreAugerlaboratory

•  Neutrinodetectors•  … 63

andCRcontinuetocontributetofundamentalphysics

•  CosmicraysandcosmologicalsourcesagainmoveintothefocusofVHEparticleandgravitationalphysics

•  Oneofthemostimportantrecentresultonelementaryparticlephysicscamefromcosmicrays:neutrinohasanonzeromass–  InterplaybetweenCRandacceleratorphysics,again

–  Solarneutrinos;KamLAND2002(reactor),GranSasso2010(accelerator),T2K2011

64

14/02/19

33

12

Malargue●

Thehighestenergycosmicrays3000km2

65

AlphaMagneticSpectrometer

LaunchedMay16,2011

Measuresinfinedetailcosmicrays<some1011eV:darkmatter,antimatter,exoticparticles

à

66

14/02/19

34

67

Thedirectprobesofcosmicparticleaccelerators

e+ e-

γ

Excessofcosmicantimatter(PAMELA,AMS-022008-2016)

68

14/02/19

35

SourcesofCRuptothekneeCherenkovtelescopes&X/gammasatellites•  MarginalevidencethatSNRaresourcesofCR

upto~1000TeVcomefrommorphologystudiesofRXJ1713-3946(H.E.S.S.2004)

•  StrikingevidencefromthemorphologyofIC443(MAGIC+Fermi/Agile2010)

•  Now~10SRNsacceleratinghadronsareknown(HESS,MAGIC,VERITAS,Fermi),plusaPevatronintheGCregion(H.E.S.S.2016)

69

Fermi,Egret

Magic,Veritas

IC443 W51:gammarayscomefromamolecularcloudseparatedfromthepulsar

Evidencethat(partofthe)CR>1019eVcomefromAGN

•  In~30000cosmicrayswithenergiesabove8EeVrecordedoveraperiodof12years,thePierreAugerObservatoryhasevidencedatmorethan5σadipoleanisotropy

•  IfUHEcosmicraysoriginatefromaninhomogeneousdistributionofsourcesandthendiffusethroughintergalacticmagneticfields,onecanexpectdipoleamplitudesgrowingwithenergy

•  Ifthesourcesweredistributedlikegalaxies,thedistributionofwhichhasasignificantdipolarcomponent,adipolarcosmic-rayanisotropywouldbeexpected

•  Followsaclaim(Auger2007)ofacorrelationwithCenA–  AlsoTelescopeArraydetectsamarginalanisotropy

70E>55EeV

E>8EeV

14/02/19

36

Astrophysicalneutrinos(2013)

•  Evidencethatthereareneutrinosabove20TeV(andupto10PeV)comingfromextragalacticsources,notGRB(probablyAGN)

71

GravitationalWaves(2015-)

72

time

10BH-BHfusions,1NS-NS…andgrowing!

14/02/19

37

FirstsimultaneousGW-gammaray-opticalobservation(2017)

73

Firstsimultaneousneutrino-gammarayobservation(2017/18)

74

14/02/19

38

Conclusion

•  CosmicRayphysicsandparticlephysicsatlaboratories/acceleratorsareasuccessfulexampleofaninterplaybetweendisciplines;after100yearsthiscooperationisstillatthecuttingedge–  Acenturyofgreatdiscoveries,andmoretocome

•  TheworkbehindthediscoveryofCRinvolvedscientistsallaroundtheworld.Itisasuccessfulexampleofinternationalcooperation

•  ThereisanaccelerationofthediscoveryincosmicrayphysicsintheXXIcentury

•  Multimessengerastrophysics!

75