PHYS 3446

Lecture #1Wednesday January 18, 2012

Dr. Andrew Brandt

1. Syllabus and Introduction

2. High Energy Physics at UTA

Thanks to Dr. Yu for developing initial electronic version of this class

Please turn off your cell-phones, pagers and laptops in class

http://www-hep.uta.edu/~brandta/teaching/sp2012/teaching.html

My Background+Research

B.S. Physics and Economics College of William&Mary 1985

PH.D. UCLA/CERN High Energy Physics 1992

(UA8 Experiment-discovered hard diffraction)

1992-1999 Post-doc and Lab Scientist at Fermi National Accelerator Laboratory

-1997 Presidential Award for contributions to diffraction

-Proposed and built (with collaborators from Brazil) DØ Forward Proton

Detector

-Physics Convenor

-Trigger Meister

1999 Joined UTA as an Assistant Professor

2004 promoted to Associate Professor

2010 promoted to Full Professor

- Funding from NSF, DOE, and Texas approaching 10M$ as PI or Co-PI

Monday August 29,

2011

PHYS 1444-004, Dr.

Andrew Brandt

My Main Research Interests

• High Energy Physics (aka Particle Physics)

• Physics with Forward Proton Detectors (detect

protons scattered at small angles)

• Fast timing detectors (How fast? Really really fast!)http://www.youtube.com/watch?v=By1JQFxfLMM&feature=related

• Triggering (selecting the events to write to tape): at

ATLAS must choose most interesting 300 out of up to

40,000,000 events/sec

• Higgs Discovery

• Weapons of Mass Destruction

Monday August 29,

2011

3 PHYS 1444-004, Dr.

Andrew Brandt

(detection of)

Grading

• Only test is a Midterm: 25%

– No Final

– Test will be curved if necessary

– No makeup tests

• Homework: 20% (no late homework)

• Lab score: 25% (details soon)

• Project: 20% (a look at early ATLAS data

or a report/presentation on important events

in particle physics?)

• Pop Quizzes: 10%

Attendance and Class Style

• Attendance:

– is STRONGLY encouraged, to aid your

motivation I give pop quizzes

• Class style:

– Lectures will be primarily on electronic media

• The lecture notes will be posted AFTER each class

– Will be mixed with traditional methods

(blackboard)

– Active participation through questions and

discussion are STRONGLY encouraged

Physics History

• Classical Physics: forces, motion, work,

energy, E&M, (Galileo, Newton, Faraday,

Maxwell)

• In modern physics (Einstein, Planck, Bohr)

we covered relativity, models for the atom,

some statistical mechanics, and finished

with a bit of discussion about the nucleus

and binding energy circa 1930 when the

neutron was discovered

• What’s new since 1930?

Physics History

• I’m going to have to respectfully disagree

with you Leonard…

• 1937 muon discovered (who ordered that?)

• With advent of particle accelerators came

particle zoo

• There was a need to classify all the new

particles being discovered and try to

understand the underlying forces and theory

Course Material • Nuclear Physics

– Models of atom

– Cross sections

– Radiation

• High Energy Experiment

– Energy deposition in matter

– Particle detector techniques

– Accelerators

• HEP Phenomenology

– Elementary particle interactions

– Symmetries

– The Standard Model

– Beyond the Standard Model

High Energy Physics at UTA

UTA faculty Andrew Brandt, Kaushik De,

Amir Farbin, Andrew White, Jae Yu along with many post-docs, graduate and undergraduate students investigate the basic forces of nature through particle physics studies at the world’s

highest energy accelerators

In the background is a photo of a sub-detector of the 5000 ton

DØ detector. This sub-detector was designed and built at UTA

and is currently operating at Fermi National Accelerator

Laboratory near Chicago.

Structure of Matter

cm

Matter

10-9m

Molecule

10-10m 10-14m

Atom Nucleus

Atomic Physics

Nuclear

Physics

High energy means small distances

Nano-Science/Chemistry10-15m

u

<10-18m

QuarkBaryon

Electron

<10-19mprotons, neutrons,

mesons, etc.top, bottom,

charm, strange,

up, down

High Energy Physics

(Hadron)

(Lepton)

Periodic Table

All atoms are madeof protons, neutronsand electrons

Helium Neon

u

d

uu

dd

Proton NeutronElectron

Gluons hold quarks togetherPhotons hold atoms together

What is High Energy Physics? Matter/Forces at the most fundamental level.

Great progress! The “STANDARD MODEL”

BUT… many mysteries

=> Why so many quarks/leptons??

=> Why four forces?? Unification?

=> Where does mass come from??

=> Are there higher symmetries??

What is the “dark matter”??

Will the LHC create a black hole

that destroys the Earth?

NO! See: http://public.web.cern.ch/Public/en/LHC/Safety-en.html

Role of Particle Accelerators

• Smash particles together

• Act as microscopes and time machines

– The higher the energy, the smaller object to be

seen

– Particles that only existed at a time just after the

Big Bang can be made

• Two method of accelerator based

experiments:

– Collider Experiments: p p, pp, e+e-, ep

– Fixed Target Experiments: Particles on a target

– Type of accelerator depends on research goals

Fermilab Tevatron and CERN LHC• Currently Highest Energy

proton-anti-proton collider

– Ecm=1.96 TeV (=6.3x10-7J/p13M Joules on 10-4m2)

Equivalent to the K.E. of a 20 ton truck at a speed 81 mi/hr

Chicago

Tevatron p

p CDF

DØ

Fermilab: http://www.fnal.gov/ ; DØ: http://www-d0.fnal.gov/ CERN: http://www.cern.ch/ ; ATLAS: http://atlas.web.cern.ch/

• Highest Energy (proton-proton) collider since fall 2009

– Ecm=14 TeV (=44x10-7J/p1000M Joules on 10-4m2)

Equivalent to the K.E. of a 20 ton truck at a speed 711 mi/hr

Currently 7 TeV collisions

1500 physicists

130 institutions

30 countries

5000 physicists

250 institutions

60 countries

The International Linear Collider

33km=

21mi

European Design

500 GeV (800 GeV)

47 km

=29 mi

US Design

500 GeV (1 TeV)

• Long~ linear electron-position colliders

• Optimistically 15 years from now

• Takes 10 years to build an accelerator and the detectors

Dr.White is co-

spokesman

of SiD detector

Particle Identification

Interaction

Point

electron

photon

jet

muonneutrino (or any non-

interacting particle

missing transverse

momentum)

Ä B

Scintillating Fiber

Silicon Tracking

Charged Particle Tracks

Calorimeter (dense)

EM hadronic

Energy

Wire Chambers

Mag

net

Muon Tracks

We know x,y startingmomenta is zero, but

along the z axis it is not, so

many of our measurements are

in the xy plane, or transverse

DØ Detector

• Weighs 5000 tons

• As tall as a 5 story building

• Can inspect 3,000,000 collisions/second

• Record 100 collisions/second

• Records 10 Mega-bytes/second

• Recording 0.5x1015 (500,000,000,000,000)

bytes per year (0.5 PetaBytes).

30’

50’

ATLAS Detector

• Weighs 10,000 tons

• As tall as a 10 story building

• Can inspect 1,000,000,000

collisions/second

• Recors 200 -300 collisions/second

• Records 300 Mega-bytes/second

• Will record 2.0x1015

(2,000,000,000,000,000) bytes each year (2

PetaByte).

The Standard Model

• Current list of elementary (i.e. indivisible) particles

• Antiparticles have opposite charge, same mass

The strong force is different from E+M and gravity!new property, color chargeconfinement - not usual 1/r2

Standard Model has been very successful

but has too many parameters, does not

explain origin of mass. Continue to probe

and attempt to extend model.

UTA and Particle Physics

Fermilab/Chicago

CERN/Geneva

ILC? U.S.?

Building Detectors at UTA

High Energy Physics Training + Jobs

EXPERIENCE:

1) Problem solving

2) Data analysis

3) Detector construction

4) State-of-the-art high speed electronics

5) Computing (C++, Python, Linux, etc.)

6) Presentation

7) Travel

JOBS:

1) Post-docs/faculty positions

2) High-tech industry

3) Computer programming and development

4) Financial

DØ Forward Proton Detector (FPD)

• Quadrupole Spectrometers

• surround the beam: up, down, in, out

• use quadrupole magnets (focus beam)

- a series of momentum spectrometers that make use of accelerator

magnets in conjunction with position detectors along the beam

line to measure the momentum and scattering angle of the proton

• Dipole Spectrometer

• inside the beam ring

in the horizontal plane

• use dipole magnet

(bends beam)

• also shown here: separators (bring beams

together for collisions)

A total of 9 spectrometers comprised of 18 Roman Pots

Data taking finished, analysis in progress (Mike Strang Ph.D. 2006)

Detector Construction

At the University of Texas, Arlington (UTA), scintillating and optical

fibers were spliced and inserted into the detector frames.

The cartridge bottom containing the detector is installed in the Roman

pot and then the cartridge top with PMT’s is attached.

One of the DØ Forward Proton Detectors built

at UTA and installed in the Tevatron tunnel

FermilabDØ

High-tech fan

Tevatron: World’s 2nd Highest Energy

Collider

Elastic Scattering Cross Section (FPD)

Single Diffractive Cross Section (FPD)

Arnab Pal (UTA PhD student)

ATLAS Forward Protons: A (10)

Picosecond Window on the Higgs Boson

Andrew Brandt, University of Texas at Arlington

A picosecond is a trillionth of a second.

This door opens ~once a second, if it opened

every 10 picoseconds it would open a hundred

billion times in one second (100,000,000)

Light can travel 7 times around the earth in

one second but can only travel 3 mm in 10 psec

Yes, I know it’s a door, not a window!

27January 12, 2010 Andrew Brandt SLAC Seminar

Central Exclusive HiggsAFP concept: adds new ATLAS sub-detectors at 220 and 420 m

upstream and downstream of central detector to precisely measure the

scattered protons to complement ATLAS discovery program.

These detectors are designed to run at a luminosity of 1034 cm-2s-1 and

operate with standard optics (need high luminosity for discovery physics)

Ex. The leading discovery channel for light SM

Higgs, H , has a branching ratio of 0.002!

You might ask: “Why build a 14 TeV collider and have 99% of your energy taken

away by the protons, are you guys crazy or what??”

beam

p’

p’AFP Detector

LHC magnets

The answer is “or what”!—ATLAS is routinely losing energy

down the beam pipe, we just measure it accurately!!!

420 m 220 mH

Note: the quest for optimal S/B

can take you to interesting places:28

n=1 n>>1

Cerenkov Effect

Use this property of prompt radiation to develop a fast

timing counter

particle

Photocathode

Dual MCP

Anode

Gain ~ 106

Photoelectron

V ~ 200V

V ~ 200V

V ~ 2000V

photon

+

+

e-

Faceplate

MCP-PMT

Micro-Channel Plate

Photomultiplier Tube

(MCP-PMT)

Ultra-fast Timing Issues

• 3 mm =10 ps

• Radiation hardness of all components of system

• Lifetime and recovery time of tube

• Backgrounds

• Multiple proton timing

Time resolution for the full detector system:

1. Intrinsec detector time resolution

2. Jitter in PMT's

3. Electronics (AMP/CFD/TDC)

4. Reference Timing

31January 12, 2010 Andrew Brandt SLAC Seminar

Laser Tests

Study properties of MCP-PMT’s:

1) How does timing depend on gain and number of pe’s

2) What is maximum rate? How does this depend on various

quantities?

3) Establish minimum gain to achieve timing goals of our detector

given expected number of pe’s (~10). Evaluate different electronics

choices at the working point of our detector

4) Eventually lifetime tests

***Ongoing laser tests very useful in developing the fastest time of

flight detector ever deployed in a collider experiment

32

LeCroy Wavemaster

6 GHz Oscilloscope

Laser Box

Hamamatsu

PLP-10

Laser

Power

Supply

33

laserlenses

filterMCP-PMT

beam splittermirror

PTF

Picosecond Test Facility

featuring initial

Undergraduate

Laser Gang (UGLG)

Undergraduate Laser

Youths? (UGLY)

January 12, 2010 Andrew Brandt SLAC Seminar

Timing vs Gain for 10 m Tube

Measured with reference tube using CFD’s and x100

mini-circuits amps, with 10 pe’s can operate at ~5E4 Gain

(critical for reducing rate and lifetime issues) With further

optimization have obtained <25 ps resolution for 10 pe’s.

34

35

0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100 120

Tim

e R

esolu

tion

(p

s)

#PE

HV 2350

HV 2450

HV 2650

HV 2750

HV 2850

Timing vs. Number of PE’s

No dependence of timing on gain if sufficient amplification!

Aside: Measuring Speed of EM Waves

• We noted that

ground plane

oscillations on

reference tube

were picked up

by second tube

• Used this to do a

3% measurement

of speed of light

(Kelly Kjornes)

36

Moving 2nd tube 2 feet from reference tube shifts pick-up

oscillation pattern by 2.05 ns

New Multi-Channel Laser Setup

37January 12, 2010 Andrew Brandt SLAC Seminar

Pre-lecture Conclusions

• Nuclear and Particle picks up where

Modern Physics left off

• One of the current frontiers of physics is

high energy or particle physics: very

interesting (I think!)

• Nobel Prize possibilities

• Other interesting areas of physics at UTA

include nano-bio physics, astrophysics,

nano-magnetism, etc.

Summary

• If you are here to learn about Nuclear/Particle Physics this should be an interesting and fun class, if you are here because you need four hours of physics….

a) get out while you still can OR

b) it will still be an interesting and fun class (up to you)

• It is an opportunity to learn about high energy physics from a high energy physicist

• Lab takes time, there will be reading outside of main text

• See me if interested in UG research project in particle physics

Monday August 29,

2011

40

Why Do Physics?

• To understand nature through experimental observations and measurements (Research)

• Establish limited number of fundamental laws, usually with mathematical expressions

• Explain and predict nature

⇒Theory and Experiment work hand-in-hand

⇒Theory generally works under restricted conditions

⇒Discrepancies between experimental measurements and theory are good for improvement of theory

⇒Modern society is based on technology derived from detailed understanding of physics

Exp.{

Theory {

PHYS 1444-004, Dr.

Andrew Brandt

Monday August 29,

2011

41

Why Do Physics Part Deux

PHYS 1444-004, Dr.

Andrew Brandt

http://www.aps.org/publications/apsnews/200911/physicsmajors.cfm

2008/2009 Graduates

1.7% unemployment

While engineering

starting salaries are

typically higher than

physicists, mid-

career salaries are

virtually identical

101k$ for engineering

99k$ for physics

Monday August 29,

2011

42

What Do Physicists Do?

PHYS 1444-004, Dr.

Andrew Brandt