From Ultra Rays to Astroparticles: A Historical Introduction to Astroparticle Physics

344 Pages·2012·7.36 MB·English

by  Wolfgang Rhode (auth.), Brigitte Falkenburg, Wolfgang Rhode (eds.)

From Ultra Rays to Astroparticles
Brigitte Falkenburg (cid:2) Wolfgang Rhode
Editors
From Ultra Rays
to Astroparticles
A Historical Introduction
to Astroparticle Physics
Editors
BrigitteFalkenburg WolfgangRhode
PhilosophyandPoliticalScience,Faculty14 Physics,Faculty2
TechnischeUniversitaetDortmund TechnischeUniversitaetDortmund
Dortmund,Germany Dortmund,Germany
ISBN978-94-007-5421-8 ISBN978-94-007-5422-5(eBook)
DOI10.1007/978-94-007-5422-5
SpringerDordrechtHeidelbergNewYorkLondon
LibraryofCongressControlNumber:2012954697
©SpringerScience+BusinessMediaDordrecht2012
Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpartof
thematerialisconcerned,specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation,
broadcasting,reproductiononmicrofilmsorinanyotherphysicalway,andtransmissionorinformation
storageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilarmethodology
nowknownorhereafterdeveloped.Exemptedfromthislegalreservationarebriefexcerptsinconnection
with reviews or scholarly analysis or material supplied specifically for the purpose of being entered
and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of
this publication or parts thereof is permitted only under the provisions of the Copyright Law of the
Publisher’slocation,initscurrentversion,andpermissionforusemustalwaysbeobtainedfromSpringer.
PermissionsforusemaybeobtainedthroughRightsLinkattheCopyrightClearanceCenter.Violations
areliabletoprosecutionundertherespectiveCopyrightLaw.
Theuseofgeneraldescriptivenames,registerednames,trademarks,servicemarks,etc.inthispublication
doesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfromtherelevant
protectivelawsandregulationsandthereforefreeforgeneraluse.
Whiletheadviceandinformationinthisbookarebelievedtobetrueandaccurateatthedateofpub-
lication,neithertheauthorsnortheeditorsnorthepublishercanacceptanylegalresponsibilityforany
errorsoromissionsthatmaybemade.Thepublishermakesnowarranty,expressorimplied,withrespect
tothematerialcontainedherein.
Copyrightforthecoverillustration:MichaelBackes,TechnischeUniversitätDortmund,http://app.tu-
dortmund.de/~backes/media/presse/Magic%201.JPG.
Printedonacid-freepaper
SpringerispartofSpringerScience+BusinessMedia(www.springer.com)
Preface
In 1912, Victor Hess discovered cosmic rays. His discovery opened the skies in
many regards: for detecting extraterrestrial particles, for making energies beyond
theMeVscaleofnuclearphysicsaccessible,forinterpretingallkindofastrophys-
icaldataintermsofcosmicmessengerparticles,andfinally,forgivingcosmology
an empirical basis. In the 1920s, it turned out that the so-called Höhenstrahlung
has an extraterrestrial origin and contains charged particles such as the electron.
The discovery of the positron in 1932 inaugurated the detection of a plethora of
new subatomic particles. With the rise of the big particle accelerators in the early
1960s, cosmic ray studies shifted from particle physics to astrophysics. The cos-
micmicrowavebackgrounddiscoveredin1965gavesupporttothebigbangmodel
of cosmology and made cosmology an empirical science. In the late 1980s, with
the experiments that measured the solar neutrino flux, part of the particle physics
communitymovedbacktocosmicraystudiesandastroparticlephysicsbegan.The
experiments of astroparticle physics use particle detectors arranged to telescopes.
Hence, astroparticle physics is doing particle physics by means of telescopes, and
viceversa,doingastrophysicsbymeansofparticledetectors.Cosmicraysaremes-
sengerparticlesthatcarryinformationaboutexplodingandcollapsingstars(inpar-
ticular,supernovae,theirremnants,andblackholes),thelarge-scalestructureofthe
universe,andthemicrowaveafterglowofthebigbang.Theirinvestigationisoneof
themostfascinatingfieldsofmodernphysics.
Thisbookmaybereadonitsownasanintroductiontoafascinatingmulti-faceted
fieldofresearch,butalsousedinadditiontoundergraduateorgraduatelecturesin
astroparticle physics. It covers the historical experiments and lines of thought to
whichlecturescannotgivesufficientattention.Thematerialpresentedheremakes
the bridge from the beginnings of radioactivity research, particle physics, astro-
physics, and cosmology in the early days of quantum theory and relativity, to the
current foundationsofphysicalknowledge,and to the questionsand methodsofa
futurephysics.Itshowsthatfundamentalresearchisfascinatingandofgreatimpor-
tance,andthatitseemsworthtremendouseffortstothephysicists.
AtthecentenaryofthepioneeringphenomenonfoundbyVictorHess,wepresent
ahistoricalintroductionintoastroparticlephysicshere.Wethinkthatthehistorical
v
vi Preface
approachisagoodthreadforunderstandingthemanyexperimentalmethods,phe-
nomena,andmodelsemployedinastroparticlephysics,thewaysinwhichtheyare
linkedtoeachother,aswellastheirrelationstotheirneighboringdisciplinesofpar-
ticlephysics,astrophysics,andcosmology.Eachofthesefieldsonitsownishighly
complex, and to learn a mixture of them before getting to the bottom of any may
beconfusingforbeginners.Wehopethatthiscomplexbodyofknowledgeismade
more transparent by a historical account of the different research traditions which
cometogetherincurrentastroparticlephysics.
Astroparticle physics has emerged from several distinct fields of research. In-
deed, these fields have not completely grown together as long as physics does
not dispose of a unified “theory of everything”. Nevertheless the models and ex-
periments of astroparticle physics are much more than provisional or piece-meal
physics.Theyarenolessandnomorethansurveysandmapsofourknowledgeof
theuniverseatasmallscaleandatalargescale.Onthewayinterraincognita,care-
fulcartographyofthedetailsisindispensable.Indeedastroparticlephysicsaimsat
establishingasmanyexperimentaldetailsaspossibleaboutcosmicrays,theirparti-
clenature,theirspectrum,theirastrophysicalsources,andthemechanismsoftheir
acceleration. But in distinction to other scientific disciplines, this gathering of de-
tailsdoesnotgiverisetoincreasingspecialization.Quitetothecontrary,thehistory
of the different branches of physics grown together in astroparticle physics shows
themergingofverydistinctscientifictraditions.
Thebookisaddressedtoundergraduateandgraduatestudentsofphysicsandto
theirteachers.Itmayserveasbackgroundmaterialforlectures.Itmaysalsoserve
thestudentsandteachersofotherfaculties,inparticularphilosophersandhistorians
of science, and everybody interested in a fascinating field of research in physics.
To historians and philosophers of science it gives an overview as well as detailed
information of a new sub-discipline of physics that has not been studied yet as a
whole,butonlyinpartialapproachestothehistoryofparticlephysics,cosmology,
etc., and to their epistemological aspects. Historians of science will read the book
as a history written by the physicists, with all the advantages and disadvantages
of objectiveexpert knowledgecombinedwith subjectivememory.Philosophersof
science will find in the book a lot of epistemological material, most of which has
been neglected by a philosophy of physics that has traditionally been focusing on
thetheoriesratherthanthephenomenaofphysics,eventhoughthelatteraremost
important constraints of the former. The history, the current shape, and the goals
of astroparticle physics raise deep epistemological questions about the grounds of
a discipline grown together from distinct scientific traditions in search for unified
knowledge.Butthesephilosophicalquestionsarekeptaparthere.Theywillbedis-
cussedinafollowervolumeonthequestionofwhatkindofknowledgeastroparticle
physicsgathersaboutparticlesfromcosmicsources.
The authors of the book reflect the various approaches to astroparticle physics.
Allofthemsubstantiallycontributedtodevelopingthemany-facetedmethodsand
totheresultsofthisfieldofresearch.Weshouldaddthatthecollectionofsubjects
presentedhereisfarfrombeingcomplete.Wethanktotheauthorsandweapologize
forallneglectedsubjectsandallthecolleaguesandtheirmeritswhichcouldnotbe
includedinthebook.
Preface vii
This volume emerged from a workshop on the history and philosophy of as-
troparticlephysicswhichtookplaceinDortmundinOctober2009,andwhichwas
supported by the German Physical Society. We would like to thank the authors,
Kirsten Theunissen from Springer, whose support made this edition possible, and
RaphaelBolinger,whopreparedAppendicesA–D.
Dortmund,Germany BrigitteFalkenburg
WolfgangRhode
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
WolfgangRhode
2 From the Discovery of Radioactivity to the First Accelerator
Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
MichaelWalter
3 DevelopmentofCosmology:FromaStaticUniversetoAccelerated
Expansion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
MatthiasBartelmann
4 Evolution of Astrophysics: Stars, Galaxies, Dark Matter, and
ParticleAcceleration . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
PeterL.Biermann
5 DevelopmentofUltraHigh-EnergyCosmicRayResearch . . . . . . 103
Karl-HeinzKampertandAlanA.Watson
6 Very-HighEnergyGamma-RayAstronomy:A23-YearSuccess
StoryinAstroparticlePhysics . . . . . . . . . . . . . . . . . . . . . . 143
EckartLorenzandRobertWagner
7 SearchfortheNeutrinoMassandLowEnergyNeutrinoAstronomy 187
KaiZuber
8 From Particle Physics to Astroparticle Physics:
ProtonDecayandtheRiseofNon-acceleratorPhysics . . . . . . . . 215
HinrichMeyer
9 TowardsHigh-EnergyNeutrinoAstronomy . . . . . . . . . . . . . . 231
ChristianSpiering
10 FromWavestoParticleTracksandQuantumProbabilities . . . . . 265
BrigitteFalkenburg
ix
x Contents
AppendixA Timetable . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
AppendixB NobelPrizes . . . . . . . . . . . . . . . . . . . . . . . . . . 305
AppendixC Textbooks. . . . . . . . . . . . . . . . . . . . . . . . . . . . 309
AppendixD BooksinHistoryofPhysics . . . . . . . . . . . . . . . . . . 315
CitationIndex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319
NameIndex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329
SubjectIndex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335
Chapter 1
Introduction
WolfgangRhode
Takingthediscoveryofthe“UltraRays”,nowadayscalled“CosmicRadiation”,by
Victor Hess 1912 as a beginning, the research field of Astroparticle Physics cel-
ebrates in 2012 its 100th Birthday. It is a unique research field, to which results
fromalargenumberofotherphysicaldisciplinescontributeandwhichtreatsfunda-
mentalquestionsofastrophysics,particlephysicsandcosmology.Inthisbook,the
developmentofAstroparticlePhysicssinceitsbeginningintheearly20thcentury
isdescribedincontributionsofauthorswhoallhaveleftdistinctivefootstepsinthe
field they are reporting about. Emphasizing the basic ideas of the development, in
this first chapter a tour d’ horizon on the connecting path between the following
contributionsisfollowed.
1.1 Rootsand Connections
At the beginning of modern physics, there were the two different approaches of
GalileoGalileiandFrancisBacontothequestionofhowthebookofnatureshould
beread.Galileiintroducedtheanalytic–synthetictechniquetosubdivideeveryphys-
icalprobleminitsproperties,toinvestigatethesepropertiesindetail,toexpressthe
experimental results – as good as possible – in the language of mathematics, and
finally to synthesize the solution to the original problem from these investigated
constituents.Bacon,tothecontrary,suggestedthatthephysicistshouldobservethe
experimentasawhole,notanatomizetheexperimentalsetupbutnoticeeveryinflu-
encingeffectandfinallyformulatethesolutionlikeajudgerenderstheverdictafter
havingcometoknowallevidence.
The rapid and very successful development of physics is a consequence of an
application of Galilei’s analytic–synthetic method. By restricting the range of the
(cid:2)
W.Rhode( )
PhysicsDepartment,TUDortmundUniversity,Otto-Hahn-Str.4,44227Dortmund,Germany
e-mail:[email protected]
B.Falkenburg,W.Rhode(eds.),FromUltraRaystoAstroparticles, 1
DOI10.1007/978-94-007-5422-5_1,©SpringerScience+BusinessMediaDordrecht2012
2 W.Rhode
analyticalinterestoftheresearchers,physicaldisciplinesandbranchesandlateron
completeengineeringfacultieswereestablished.A‘physicaldiscipline’inthisway
appearsasphysicswithinaspecialbranchofinterest.
It seems that the analytic–synthetic way of research is perfectly adapted to the
needsofphysics–solongafurtherextensionoftheanalysis,abettercontrolofthe
experimentalparametersoranenlargementoftherangeofmeasurementsinalabo-
ratoryisstillpossible.Buthowcanoneproceed,ifthereisnooronlylimitedcontrol
overtheexperimentalparameters,iftheimprovementoftheresolutionofthedetec-
tor does not lead anymore to a better understanding of a subsystem, which again
solves the primary question? Then one might feel unwillingly thrown in the posi-
tion of Bacon’s judge. The ‘evidence’ here means results of measurements, often
correlated,inexperiments,whichcanbecontrolledonlypartiallyandinafigurative
sense.The‘verdict’reliesonasimultaneoussolutionofthe‘evidence’-puzzlewith
physical,mathematicalorevenmodernstatisticalmethods.
Since new techniques and actual research always are in contradiction with this
uncontrolledoruncontrollablepartoftheexperiments,newscienceisinthissense
alwaysattheborderlinebetweenGalileoandBacon.Howeasyforexampleques-
tionsinparticlephysicscouldbeanswered,ifonlythephysicisthadthefreedomto
only switch on the reaction that he wants to investigate! The subject of this book,
thedevelopmentofAstroparticlePhysicsasaphysicaldisciplineisanexampleof
howphysicalquestionsaresolvedinamuchmore‘Baconian’than‘Galileian’way.
Also a second approach to the question of the special way of Astroparticle
Physics concerns nothing less than the goal of all physical research. The episte-
mological key question is: Does one intend to draw a picture of the world, which
isastrueaspossible,orshoulditbeassimpleandbeautifulaspossible?Giventhe
smallpartofthephysicalworld,inwhichsingularmeasurementsarepossible,the
truth-requirementdepictsthisworldasapatchworkofapproximations.Therequire-
ment of beauty and simplicity on the other hand leads into that Platonic world in
whichthenatureisdescribedbyasmallnumberofforces.Thepriceforthisbeauty
is,however,aninclusionofassumptionsandofextrapolationsinthemathematical
model and finally a loss of provable truth. While Mach’s critical positivistic ques-
tions helped to identify the right questions in the dusk of classical physics, in the
dawnofquantummechanicsandthetheoryofrelativityphysicistsquicklyadopted
thegoaloffindingtheunifyingworldformula.
The heart of most physicists who think about this problem still seems to beat
moreforthebeautymodelthanfortheuglytruth.Thereforeitisnosurprisethatin
disciplines like elementary particle physics, the search for a mathematical expres-
sionoftheunifiedforcesbetweentheparticlesisoneofthedrivingforcestobuild
step by step larger and faster and more precise and better controlled experiments.
Giventhesuccessofthestandardmodelofelementaryparticlephysicsindescribing
theresultsofthesehighprecisionexperiments,istherestillroomforAstroparticle
Physicsonthebeautysideofthatdiscussion,oristhisdisciplinecondemnedtolive
withitspassivemeasurementsinapositivisticpatchworkworld?
Theanswertothisquestionhastwosides.First,onehastobeawarethatasearch
for more beauty in describing the theory alone is not a sufficient reason to jus-