Prabhakar Palni Physics and Astronomy This dissertation is approved, and it is acceptable in ...

190 Pages·2014·6.41 MB·English

Prabhakar Palni
Candidate
Physics and Astronomy
Department
This dissertation is approved, and it is acceptable in quality and form
for publication:
Approved by the Dissertation Committee:
Dr. Sally Seidel, Chairperson
Dr. Igor Gorelov
Dr. Flera Rizatdinova
Dr. Rouzbeh Allahverdi
Dr. Leo Bitteker
Evidence for the Heavy Baryon
Resonance State ⇤ 0 Observed with the
⇤
b
CDF II Detector, and Studies of New
Particle Tracking Technologies Using the
LANSCE Proton Beam
by
Prabhakar Palni
B.Sc., Goa University, 2004
M.Sc., University of Mumbai, 2006
DISSERTATION
Submitted in Partial Fulfillment of the
Requirements for the Degree of
Doctor of Philosophy
Physics
The University of New Mexico
Albuquerque, New Mexico
May, 2014
ii
c 2014, Prabhakar Palni
�
iii
Dedication
I dedicate this work to my beloved sister.
iv
Acknowledgments
I would like to begin by thanking my advisor Prof. Sally Seidel, for her constant
support and guidance throughout my research. Importantly, I am very thankful to
herformotivatingmeandshowingconfidenceinmerightfromthebeginningthrough
the up and down phases of my research work.
I would like to thank my co-advisor, Prof. Igor Gorelov, for his guidance and
instruction in the analysis of the ⇤ 0 resonance state in the CDF and ROOT software
⇤b
environments. His mentoring and help in computer-related technical problems was
very crucial when I first started my journey in the experimental particle physics field.
I would like to thank Martin Hoeferkamp for his help in the study of real time
monitoring of charged particle beam profile and fluence. He has tremendously helped
me during the development of the diode array technique carried out at the LANSCE
facility of Los Alamos National Laboratory as well as in our laboratory. I would like
to thank the Weapons Neutron Research facility at LANSCE and its associated sta↵
for operating the facility during the experiments.
I would like to thank Satyajit Behari for collaborating on the Inclusive BMC
project. I thank the members of the CDF Collaboration and the sta↵ at Fermilab.
I want to thank Prof. Rouzbeh Allahverdi for mentoring and also for serving on
my dissertation committee. I would like to thank you for your Cosmology, Electro-
dynamics, and Quantum Mechanics classes. I thoroughly enjoyed your courses and
class discussions.
Many thanks to Prof. Flera Rizatdinova and Prof. Leo Bitteker for serving on
my dissertation committee. Your feedback, comments, and advice on my dissertation
have helped me improve my standards.
Many thanks to all the faculty members who have instructed me at the UNM
DepartmentofPhysicsduringtheseyears. Iamverygratefultomyteachersfrommy
school, college, andUniversityfortheirguidanceineducationandtowardsmycareer.
Specially, I would like to thank Ms. Ranebai, Fenwick John, Dasharath Shetgaonkar,
Lawrence Bosco, Rajendra Kanekar, Benedict Soares, Prof. A. Narsale, Dr. M.R.
Press, Prof. A.A Rangwala, Prof. V.H. Kulkarni, and Charudatt Kadolkar.
Iwouldliketothankmyparents, myfriends, andmybestfriendsVenkateshVeer-
araghavan, Francisco Fernandes, Krishnkumar Chauhan, Vikrant Sawant, Mithun
Shirodkar, Surya Kamulkar, and Jigyasa Rana for their unconditional support, love,
and constant encouragement for the past six years.
v
Evidence for the Heavy Baryon
Resonance State ⇤ 0 Observed with the
⇤
b
CDF II Detector, and Studies of New
Particle Tracking Technologies Using the
LANSCE Proton Beam
by
Prabhakar Palni
B.Sc., Goa University, 2004
M.Sc., University of Mumbai, 2006
Ph.D., Physics, University of New Mexico, 2014
Abstract
To discover and probe the properties of new particles, we need to collide highly
energetic particles. The Tevatron at Fermilab has collided protons and anti-protons
at very high energies. These collisions produce short lived and stable particles,
some known and some previously unknown. The CDF detector is used to study
the products of such collisions and discover new elementary particles. To study
the interaction between high energy charged particles and the detector materials
often requires development of new instruments. Thus this dissertation involves a
measurement at a contemporary experiment and development of technologies for
related future experiments that will build on the contemporary one.
Using data from proton-antiproton collisions at ps = 1.96TeV recorded by the
CDF II detector at the Fermilab Tevatron, evidence for the excited resonance state
vi
⇤ 0 is presented in its ⇤0⇡ ⇡+ decay, followed by the ⇤0 ⇤+⇡ and ⇤+ pK ⇡+
⇤b b � b ! c � c ! �
decays. The analysis is based on a data sample corresponding to an integrated lu-
minosity of 9.6fb 1 collected by an online event selection process based on charged-
�
particle tracks displaced from the proton-antiproton interaction point. The signifi-
cance of the observed signal is 3.5�. The mass of the observed state is found to be
5919.22 0.76 MeV/c2 in agreement with similar findings in proton-proton collision
±
experiments.
To predict the radiation damage to the components of new particle tracking
detectors, prototype devices are irradiated at test beam facilities that reproduce
the radiation conditions expected. The profile of the test beam and the fluence
applied per unit time must be known. We have developed a technique to monitor in
real time the beam profile and fluence using an array of pin semiconductor diodes
whose forward voltage is linear with fluence over the fluence regime relevant to, for
example, silicon tracking detectors in the LHC upgrade era. We have demonstrated
this technique in the 800 MeV proton beam at the LANSCE facility of Los Alamos
National Laboratory.
vii
Contents
List of Figures xiv
List of Tables xxiii
1 Introduction 1
2 Theoretical Overview and Motivation 4
2.1 Standard Model of Particle Physics . . . . . . . . . . . . . . . . . . . 4
2.2 Elementary Particles of Matter and Fundamental Forces in Nature . . 5
2.3 Mesons and Baryons . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.4 Lagrangian Formulation of the Quantum Field Theory . . . . . . . . 11
2.5 The Mathematical Framework of the Electromagnetic Interaction . . 12
2.6 The Mathematical Framework of the Strong Interaction . . . . . . . . 14
2.7 Heavy Quark E↵ective Theory . . . . . . . . . . . . . . . . . . . . . . 16
2.7.1 QCD Lagrangian for Quark-gluon Interactions . . . . . . . . . 17
2.7.2 HQET Lagrangian . . . . . . . . . . . . . . . . . . . . . . . . 19
viii
Contents
2.7.3 Flavor Symmetry Between the b and c Heavy Quarks . . . . . 19
2.7.4 Spin Symmetry of the Heavy Quarks . . . . . . . . . . . . . . 20
2.7.5 Spin Symmetry and Flavor Symmetry Breaking . . . . . . . . 21
2.7.6 Application of HQET to the ⇤ 0 . . . . . . . . . . . . . . . . . 22
⇤b
3 The Tevatron Accelerator and the CDF Experiment 27
3.1 The Tevatron Accelerator . . . . . . . . . . . . . . . . . . . . . . . . 27
3.1.1 Proton Production and Acceleration . . . . . . . . . . . . . . 28
3.1.2 Antiproton Production and Acceleration . . . . . . . . . . . . 29
3.1.3 Tevatron Performance and Statistics . . . . . . . . . . . . . . 30
3.2 The CDF Detector in Run II . . . . . . . . . . . . . . . . . . . . . . 31
3.2.1 Standard Definitions and Coordinate Systems . . . . . . . . . 33
3.2.2 The Tracking System Parameters . . . . . . . . . . . . . . . . 36
3.2.3 Silicon Tracking Systems . . . . . . . . . . . . . . . . . . . . . 38
3.2.4 Layer 00 (L00) . . . . . . . . . . . . . . . . . . . . . . . . . . 40
3.2.5 Silicon Vertex Detector II (SVX II) . . . . . . . . . . . . . . . 41
3.2.6 Intermediate Silicon Layers . . . . . . . . . . . . . . . . . . . 41
3.2.7 Central Outer Tracker . . . . . . . . . . . . . . . . . . . . . . 42
4 Trigger System and Data Acquisition (DAQ) 45
4.1 Level 1 Trigger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
ix
Contents
4.2 Level 2 Trigger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
4.3 Level 3 Trigger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
4.4 Two Track Trigger . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
5 ⇤ 0 Measurement 49
⇤b
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
5.2 Possible Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
5.3 Data Sample and Trigger . . . . . . . . . . . . . . . . . . . . . . . . . 54
5.4 BStNtuple Data and Conditions . . . . . . . . . . . . . . . . . . . . . 55
5.5 Monte Carlo Simulation Data . . . . . . . . . . . . . . . . . . . . . . 60
5.6 Mass Di↵erence Spectrum for ⇤ 0 Candidates . . . . . . . . . . . . . 60
⇤b
5.7 Track Quality Requirements . . . . . . . . . . . . . . . . . . . . . . . 61
5.8 ⇤0 Analysis Cuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
b
5.8.1 Optimization of the Total Transverse Momentum
p (⇤0) Selection Requirement . . . . . . . . . . . . . . . . . . 67
T b
5.8.2 OptimizationoftheDecayPionTransverseMomentump (⇡ )
T b�
Selection Requirement . . . . . . . . . . . . . . . . . . . . . . 69
5.8.3 Proper Lifetime of ⇤0 . . . . . . . . . . . . . . . . . . . . . . . 70
b
5.8.4 Impact Parameter d (⇤0) . . . . . . . . . . . . . . . . . . . . 73
| 0 b |
5.8.5 Yields of the ⇤0 Signal . . . . . . . . . . . . . . . . . . . . . . 73
b
5.8.6 Fitter of the ⇤0 Signal . . . . . . . . . . . . . . . . . . . . . . 74
b
x