discovery potential of quantum black holes in add model with the cms detector a thesis submitted to

137 Pages·2013·13.03 MB·English

DISCOVERYPOTENTIALOFQUANTUMBLACKHOLESINADDMODELWITH
THECMSDETECTOR
ATHESISSUBMITTEDTO
THEGRADUATESCHOOLOFNATURALANDAPPLIEDSCIENCES
OF
MIDDLEEASTTECHNICALUNIVERSITY
BY
HAL˙ILGAMSIZKAN
INPARTIALFULFILLMENTOFTHEREQUIREMENTS
FOR
THEDEGREEOFDOCTOROFPHILOSOPHY
IN
PHYSICS
AUGUST2011
Approvalofthethesis:
DISCOVERYPOTENTIALOFQUANTUMBLACKHOLESINADDMODELWITH
THECMSDETECTOR
submitted by HALI˙L GAMSIZKAN in partial fulfillment of the requirements for the degree
of
DoctorofPhilosophy inPhysics Department,MiddleEastTechnicalUniversityby,
Prof. Dr. CananO¨zgen
Dean,GraduateSchoolofNaturalandAppliedSciences
SinanBilikmen
HeadofDepartment,Physics
Prof. Dr. MeltemSerin
Supervisor,PhysicsDepartment
ExaminingCommitteeMembers:
Prof. Dr. AliUlviYılmazer
AU¨,Eng. Physics
Prof. Dr. MeltemSerin
METU,Physics
Prof. Dr. MehmetZeyrek
METU,Physics
Prof. Dr. Mu¨geBoz
HacettepeU¨.,Eng. Physics
Prof. Dr. Altug˘ O¨zpineci
METU,Physics
Date:
Iherebydeclarethatallinformationinthisdocumenthasbeenobtainedandpresented
in accordance with academic rules and ethical conduct. I also declare that, as required
bytheserulesandconduct,Ihavefullycitedandreferencedallmaterialandresultsthat
arenotoriginaltothiswork.
Name,LastName: HAL˙ILGAMSIZKAN
Signature :
iii
ABSTRACT
DISCOVERYPOTENTIALOFQUANTUMBLACKHOLESINADDMODELWITH
THECMSDETECTOR
Gamsızkan,Halil
Ph.D.,DepartmentofPhysics
Supervisor : Prof. Dr. MeltemSerin
August2011,120pages
Withthelongawaitedstart-upoftheLHC,TeVscalephysicsisnowinreachoftheparticles
physicists to explore. There are many questions about the nature to be answered, and many
moretheoriestobetestedtryingtoanswerthem.
TheADDmodelofextradimensionsisonesuchmodel,writtentoaddressthelargemasshi-
erarchybetweenthetwofundamentalenergyscalesinnature,theelectroweakandthePlanck
scales. ADD model predictsstronger gravity atsub-millimeter distance scales, which would
then lead to an interesting physical object to be produced at proton collusions at the LHC:
Tinyquantumblackholes.
In this thesis we study the discovery potential of CMS for quantum black hole events for
proton-proton collusions at ps = 14 TeV. Our study details the trigger response of CMS,
variouscriteriaandmethodsforbackgroundrejection,a↵ectofexperimentaluncertaintieson
measurements,fordi↵erentmodelparametervalues.
Keywords: ADDModel,ExtraDimensions,BlackHoles,CMS,LHC
iv
¨
OZ
ADDMODEL˙IKUANTUMKARADEL˙IKLER˙INCMSDEDEKTO¨RU¨ ˙ILE
KES¸FED˙ILMEPOTANS˙IYEL˙I
Gamsızkan,Halil
Doktora,FizikBo¨lu¨mu¨
TezYo¨neticisi : Prof. Dr. MeltemSerin
Ag˘ustos2011,120sayfa
LHC’nin uzun su¨redir beklenen ac¸ılıs¸ıyla, TeV enerjilerinde fizik yapmak artık parc¸acık
fizikc¸ileri ic¸in mu¨mku¨n hale gelmis¸ bulunuyor. Dog˘a’ya dair cevaplanması gereken pek c¸ok
soru,vebusorularaverdiklericevaplarınsınanmasıgerekendahadac¸okkurambulunuyor.
ADDekboyutmodelidebukuramlardanbiriolupdog˘adakibilinenikitemelenerjio¨lc¸eg˘i–
elektrozayıfvePlancko¨lc¸ekleri–arasındakibu¨yu¨kfarkıac¸ıklayabilmekamacıylayazılmıs¸tır.
ADDmodelininmilimetre’denku¨c¸u¨kmesafelerdeku¨tlec¸ekimkuvvetiningu¨c¸lendig˘ivarsayımı
LHC’deki proton c¸arpıs¸malarında ilginc¸ bir fiziksel nesnenin u¨retimi sonucunu beraberinde
getirir,yanikuantumkaradeliklerin.
Bu tezde ps = 14 TeV enerjide proton-proton c¸arpıs¸maları ic¸in CMS dedekto¨ru¨nu¨n kuan-
tumkaradelikolaylarınıkes¸ifpotansiyelic¸alıs¸ılmıs¸tır. C¸alıs¸mamızfarklımodelparametresi
deg˘erleri ic¸in CMS tetikleyicisinin davranıs¸ı, fon olaylarının reddedilmesi ic¸in c¸es¸itli kriter
veyo¨ntemler,deneyselbelirsizliklerino¨lc¸u¨mlereetkisigibibas¸lıklarıkapsar.
AnahtarKelimeler: ADDModeli,Ekboyutlar,Karadelikler,CMS,LHC
v
Ailemevetu¨msevdiklerimeithafolunur..
vi
ACKNOWLEDGMENTS
Thisthesiswouldn’texistwithoutthehelpandsupportofmanypeople,includingMehmet
Zeyrek,AlbertdeRoeck,MeltemSerin,Sezenusta,C¸ig˘demKanberog˘luandtheCMS
collaboration,bothpastandpresentmembers. Thankyou,eachandeveryoneofyou.
IalsowouldliketothankMETUDepartmentofPhysicsfortheirsupportinmystudies,
TAEKforsupportingmyvisitsatCERN,CERNforbeingahome,aschoolandanexcellent
placetodoresearch,andtheMETUNCCcampusforbeingthemostwelcomeandquiet
homeinthefinalstageofmythesisstudies.
Pekc¸okinsanınkatkısıolmadanbutezortayac¸ıkamazdı;bunlardaneno¨nemlileriMeltem
Serin,MehmetZeyrek,AlbertdeRoeck,Sezenusta,C¸ig˘demKanberog˘lu,veCMS
kolaborasyonundabulunanvebulunmus¸ kis¸ilerdir. Herbirinizeayrıayrıtes¸ekku¨rederim.
Ayrıcac¸alıs¸malarımaverdikleridestekic¸inODTU¨ FizikBo¨lu¨mu¨ne,yinedesteg˘iyleCERN
ziyaretlerimimu¨mku¨nkılanTAEK’e,hembirev,hembirokulhemdekusursuzbiraras¸tırma
ortamısag˘ladıg˘ıic¸inCERN’e,vetezc¸alıs¸malarımınsonas¸amalarınıgerc¸ekles¸tirirkenbana
samimivehuzurlubirortamsag˘layanODTU¨ KKK’yates¸ekku¨ru¨ birborc¸ bilirim.
vii
TABLE OF CONTENTS
ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
O¨Z . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
ACKNOWLEDGMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
TABLEOFCONTENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
LISTOFTABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xii
LISTOFFIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiv
CHAPTERS
1 STANDARDMODEL,ANDBEYOND . . . . . . . . . . . . . . . . . . . . 1
1.1 HierarchyofScales . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 Theorieswithextradimensions . . . . . . . . . . . . . . . . . . . . 7
1.3 Kaluza-KleinTheory . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.4 LargeExtraDimensions . . . . . . . . . . . . . . . . . . . . . . . . 11
1.4.1 PhenomenologyofLargeExtraDimensions . . . . . . . . 15
Strongergravity . . . . . . . . . . . . . . . . 15
KKexcitations . . . . . . . . . . . . . . . . . 15
GravitonProduction . . . . . . . . . . . . . . 15
BlackHoleProduction . . . . . . . . . . . . 15
1.4.2 Downsides,problemsandopenquestions . . . . . . . . . 16
1.4.3 CurrentLimitsonADDModelParameters . . . . . . . . 17
2 BLACKHOLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.1 TypesofBlackHoles . . . . . . . . . . . . . . . . . . . . . . . . . 19
Supermassiveblackholes . . . . . . . . . . . 19
Stellarblackholes . . . . . . . . . . . . . . . 19
Primordial . . . . . . . . . . . . . . . . . . . 19
viii
Quantum(higherdimensional)blackholes . . 19
2.2 TheSchwarzschildBlackHole . . . . . . . . . . . . . . . . . . . . 20
2.2.1 DerivationoftheSchwarzschildmetric . . . . . . . . . . 20
2.2.2 Alternativecoordinatesystems . . . . . . . . . . . . . . . 24
2.2.3 Kruskal-SzekeresCoordinatesandtheMaximallyExtended
SchwarzschildSolution . . . . . . . . . . . . . . . . . . . 26
2.3 ConformalDiagrams . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.4 ChargedBlackHoles . . . . . . . . . . . . . . . . . . . . . . . . . 30
2.5 RotatingBlackHoles . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.6 ClassicalBlackHoleThermodynamics . . . . . . . . . . . . . . . . 35
2.6.1 Penroseprocess . . . . . . . . . . . . . . . . . . . . . . . 35
Thezerothlaw . . . . . . . . . . . . . . . . . 38
Thefirstlaw . . . . . . . . . . . . . . . . . . 38
Thesecondlaw . . . . . . . . . . . . . . . . 38
Thethirdlaw . . . . . . . . . . . . . . . . . 39
2.7 TheEvaporatingBlackHole. . . . . . . . . . . . . . . . . . . . . . 39
2.7.1 UnruhE↵ect . . . . . . . . . . . . . . . . . . . . . . . . 39
2.7.2 HawkingRadiation . . . . . . . . . . . . . . . . . . . . . 44
3 QUANTUMBLACKHOLES . . . . . . . . . . . . . . . . . . . . . . . . . 46
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
3.2 BlackHoleFormation . . . . . . . . . . . . . . . . . . . . . . . . . 47
3.3 Decayofblackholes . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Baldingphase . . . . . . . . . . . . . . . . . 48
Spin-downphase . . . . . . . . . . . . . . . 48
Schwarzschildphase. . . . . . . . . . . . . . 49
Planckphase . . . . . . . . . . . . . . . . . . 49
3.4 DetailsoftheSchwarzschildPhase . . . . . . . . . . . . . . . . . . 49
3.5 IndirectIndicationsofBlackHoleProduction . . . . . . . . . . . . 51
3.6 HowSafeisBlackHoleProductiononEarth? . . . . . . . . . . . . 52
3.7 FirstLimitsonQuantumBlackHoleProduction . . . . . . . . . . . 54
ix
4 OBSERVINGQUANTUMBLACKHOLES . . . . . . . . . . . . . . . . . 56
4.1 LHC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
4.2 TheCompactMuonSolenoid . . . . . . . . . . . . . . . . . . . . . 64
4.2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 64
4.2.2 ConventionsandCoordinates . . . . . . . . . . . . . . . . 65
4.2.3 DetectorComponents . . . . . . . . . . . . . . . . . . . . 67
4.2.3.1 Tracker . . . . . . . . . . . . . . . . . . . . . 67
4.2.3.2 ECAL . . . . . . . . . . . . . . . . . . . . . 70
4.2.3.3 HCAL . . . . . . . . . . . . . . . . . . . . . 71
4.2.3.4 TheMuonSystem . . . . . . . . . . . . . . . 74
4.2.3.5 TriggerandDataAcquisition . . . . . . . . . 76
4.2.3.6 SoftwareandComputing . . . . . . . . . . . 78
5 SIMULATIONSOFHIGHERDIMENSIONALBLACKHOLES . . . . . . 80
5.1 AVirtualExperiment . . . . . . . . . . . . . . . . . . . . . . . . . 80
5.1.1 GeneratingBlackHoleEvents . . . . . . . . . . . . . . . 80
5.1.2 SimulatingBlackHoleEvents . . . . . . . . . . . . . . . 82
5.1.3 PhysicsObjectsandPreselection . . . . . . . . . . . . . . 84
Jetreconstruction . . . . . . . . . . . . . . . 85
Electronreconstruction . . . . . . . . . . . . 86
Muonreconstruction . . . . . . . . . . . . . 87
Photonreconstruction . . . . . . . . . . . . . 89
5.1.4 StandardModelBackgroundProcesses . . . . . . . . . . 90
5.1.5 BlackHoleDecayCharacteristics . . . . . . . . . . . . . 91
5.1.6 TriggeringBHEvents. . . . . . . . . . . . . . . . . . . . 99
5.1.7 SystematicE↵ects . . . . . . . . . . . . . . . . . . . . . 100
PDFuncertainties . . . . . . . . . . . . . . . 100
Theoreticaluncertainties . . . . . . . . . . . 101
Jetenergyscale(JES) . . . . . . . . . . . . . 101
5.1.8 SelectingBlackHoleEvents . . . . . . . . . . . . . . . . 102
5.1.9 ArtificialNeuralNetworkSelection . . . . . . . . . . . . 103
x