from physics graduate student in the '70s to observing supernovae today

Charling Tao, Sulak Festschrift, Oct 21-22,2005

A Festschrift and Conference onTHE GOLDEN AGE OF PARTICLE

PHYSICS AND ITS LEGACY Boston University

In honour of Lawrence Sulak

From Physics Graduate Student in the '70s to Observing Supernovae

Today

Charling TaoCentre de Physique des Particules de Marseille

IN2P3/CNRS and U. MéditerranéeITA NAOC Beijing


ForewordWe would particularly be interested in hearing your

thoughts on

``The life of a physics graduate student in the '70's".

OK! The title of your talk is:

From Physics Graduate Student in the '70s to Observing Supernovae Today

Aie !!Yaie!!! I am not a sociologist!!!!

wish I had Tom Wolfe’ s talent for a « I am Charlotte Simmons » speech!

Perhaps I could talk about my present work

on SN and Dark Energy. Would be easier for me…

:-*


My graduate years: 1975-1979

My Thesis (R. Wilson) :

The Structure and Formation of Hadrons: An Experiment with a Muon Beam of 219 GeV on a Hydrogen Target.

Harvard U.

Test of QCD:logarithmic breaking of scale invariance

Frontiers of physics at the time


My Harvard graduate school environment

Adviser: Richard Wilson, (+ A.L. Sessoms + T. Loomis)

Teachers: Sidney Coleman : QFT (John Lo Secco)

Shelly Glashow: Group Theory

Alvaro de Rujula: Weak Interactions

Steven Weinberg: General Relativity and Cosmology

Carlo Rubbia: Particle Physics

Howard Georgi,…Lots of other people around at the time: N. Ramsey, P. Martin, F.Pipkin, K. Strauch, Ed Witten, D. Politzer, G. t’Hooft, P. MacIntyre, W. Skocpol, Tinkham, ….

Students at the time present today ; Witold Kozanecki, Jim Strait, Michael Levi, Bruce Cortez, Ian Affleck, Dave Hannah, Wesley Smith, …

:-)


Harvard PhD 1979, 10/20 in particle physics

•AFFLECK, IAN KEITH,. Some Results on Vacuum Decay. (Coleman)

•ALVAREZ, ORLANDO, Conformal Invariance in Quantum Field Theory. (Weinberg)•DAVIS, SAMUEL, Predictions and Limitations of Perturbative QCD. (Georgi)•DE LUCCIA, FRANK JOSEPH, The Fate of the False Vacuum: Induced Decay and Gravitational Effects on Spontaneous Decay. (Coleman)•RICH, JAMES ARNOLD, Trimuon Production by High Energy Neutrinos. (Rubbia)•ROCEK, MARTIN,. Aspects of Spontaneous Symmetry Breakdown of Supersymmetry. (Wu)•SHEIMAN, JOHATHAN LEWIS, Topics in the Theory of Leptoproduction. (Georgi)•SMOLIN, LEE, Studies in Quantum Gravity. (Coleman)•SOBELMAN, GERALD EDWARD, Asymptotic Estimates and Borel Resummation for a Doubly Anharmonic Oscillator. (Coleman)•TAO, CHARLING SUN, The Structure and Formation of Hadrons: An Experiment with a Muon Beam of 219 GeV on a Hydrogen Target. (Wilson)


1975 class: 32 graduate students

1 female and only 1 other 6 years before!

:-*

Year after : 2 female graduate students

Since then, at least 1 graduating /year

Not great! But not 0

Thank you Larry

(and Beth)

for the conscious effort to bring more women in science


What did I learn from Graduate school in the 70’s?

The Feynman Problem Solving Algorithm: 1) Write down the problem. 2) Think very hard. 3) Write down the solution.

:-)



- A lot of physics, and detector building, of course,- need to work hardBut more important is the Scientific Method When faced with any problem: Don’t be afraid, ask questions

And do not forget to be socially conscious and active

Example of Larry : an ever young, enthusiastic and

curious mind


Physics is an art, the art of unveiling

the invisible

What is Physics?


What is Physics?

Physics is a language, a « universal » human language that

translates the « real » world into something « understandable »



There are many ways to do physics

and understand NatureReductionnist / Emergent

Theoretical / experimental/ phenomenology

Different fieldsChoose one path in graduate

school and learn the techniques


Why did I do a thesis on tests of QCD in Deep Inelastic Muon Scattering in 1975 ?

And why SNIa search today?

The Larry Sulak/Harvard Spirit

Frontiers of Physics


(


1970’s frontiers of physics?

e

u

d

e

c

s

t

b

leptons

quarks

3 fermion families

‘H0’

interactions

Z0 , W,W

g

‘G’

Vector bosons of interactions

electromagnetic

strong

weak

gravitation

Fundamental particles



Completing our knowledge of Fundamental Particle constituents of matter

and Fundamental interactions

e

u

d

e

c

s

t

b

leptons

quarks

3 fermion families

‘H0’

interactions

Z0 , W,W

g

‘G’

Vector bosons of interactions

electromagnetic

strong

weak

gravitation

Fundamental particles


The Golden Age of particle physics

In 1950-s : advent of particle accelerators

beams of electrons or protons with high kinetic energy.

the 4.5-inch model cyclotron built by Lawrence and Livingston.

Oct. 20, 1955: discovery of the antiproton


High energy physics

many new particles

new classification: leptons, mesons, baryons

« the eightfold way » Gell-man & Neeman

Nobel Prize in Physics 1969

Leptons and quarks

Can plan the experiments and repeat them! Particle physics second name



Towards the Standard Model of the Fundamental interactions SU(3) x SU(2) x U(1)

- Asymptotic freedom: Quantum Chromodynamics (QCD)

1973

- Unification of weak and electromagnetic interactions (discovery of Neutral currents)

Steven Weinberg Abdus SalamSheldon Glashow



Completing the particle constituent table

- J/Psi discovered (S.Ting et al., Richter et al.)

evidence for charm, postulated in 1973 (GIM)

- tau lepton (M. Perl et al.): Indication for a third family

~1975

Completing the third family

1977: beauty (Lederman et al.)

1995: top quark discovery

Nobel for v beams and v


1980’s: Triumph of the Standard Model

• Unification electromagnetism and weak interaction

Prediction of W, Z observed at CERN UA1/2 experiments (C. Rubbia et al….)

First W

First Z


Where was ?

IMB

Proton decay

+ Neutrino

Osc.

+ SN1987A


Next frontiers ? Beyond the SM of particle physics

First hint with neutrino masses ?

First hint of neutrino masses:

L. Wolfenstein


Solar neutrino problem

1970

600 tons of C2Cl4e + 37Cl 37Ar + e-

Homestake

A pioneering experiment…

R. Davis


Probing the Universe with neutrinos

SuperKamiokande neutrino image of the Sun

Pioneering Involvement in neutrino telescopesDUMAND started in 1976

IMB/ SuperK in 1978/1979


70 m

12 lines (900 PMTs) 25 storeys / line 3 PMTs/storey

350 m

100 m

14.5 m

Junctionbox

Readout cables

40 km toshore

2500 m

storey

Horizontal layout

The ANTARES underwater detector in the Mediterranean sea

P.Coyle


)


Next frontiers

Quantum theory• SUSY• Superstrings• Quantum Gravity

Cosmology

• Dark Matter

• Dark Energy

Accelerator physics is fundamental

but new physics hints could be coming

from « astro » and « cosmo » data

(Back to Cosmic Ray physics!)

New particles?

Extra dimensions?

Negative energies?

Space topologies?

Violation of Lorentz invariance?

Is the cosmological constant, constant?

What is its relationship with quantum vacuum fluctuations?


A mysterious Universe

Ordinary Matter: 4%

2/3

Dark Energy

1/3 Dark Matter

Position 1st peak =1.02 +/- 0.02

Ratio (2/1) peaksB =0.046 +/- 0.006

Definition: c (c=10-29 g/cm3)

CMB, + SN, clusters, galaxies redshift surveys, Weak Lensing, …

Concordant CDM model with

Cold Dark Matter and Cosmological constant

WMAP

Flat universe


Why SNIa search today?

Mystery of the Dark Universe ! (Michael Levi)• What expertise do we bring to the field?

Handling of large sample of data• Control of systematics: from a 2 measurement to a

credible result• SNLS is one step• Nearby supernovae program VERY important!• SNAP/JDEM 1% measurement

Today’s Frontiers of physics


Different standardisation methods

Before: mB After, eg, stretch correction: mBcor = mB – (s-1)

Different standardisation methods : stretch (SCP), MLC2k2 (HiZ), m15, ...


SN Ia in 2004: A selection by Riess et al, astro-ph 0402512

+ Low z : 0.01 < z < 0.15• Calan-Tololo (Hamuy et al., 1996) : 29 • CfA I (Riess et al. 1999): 22• CfA II (Jha et al, 2004b): 44

16 new SN Ia with HST (GOOD ACS Treasury program)

6 / 7 existing with z >1.25 + Compilation (Tonry et al. 2003): 172 with changes from…

* Knop et al, 2003, SCP : 11 new 0.4 < z < 0.85

reanalysis of 1999, Perlmutter et al.

* 15 / original 42 excluded/inaccurate colour measurements and uncertain classification

* 6 /42 and 5/11: fail « strict SNIA » sample cut

* Barris et al, 2003, HZT: 22 new: varying degrees of completeness on photometry and spectroscopy records

* Blakesly et al, 2003 : 2 with ACS on HST


A m=0.27 shift of low z data

Shift z <0.15 data by m= 0.27

m= 0.43 +/-0.2 and = 0 +/-0.34

Use Kosmoshow by A. Tilquin!

No need for

But Universe is not flat!


The CFHT Legacy Survey

Supernovæ Program

SNLS

http://snls.in2p3.fr/people/snls-members.html


The CFHT Legacy Survey Supernovæ Program

Extra collaborators :

VLT: ESO, Portugal, Sweden, UK.

Keck: US.

Gemini: UK, US.

Canada and France

(CPPM)

http://www.in2p3.fr/

http://www-dapnia.cea.fr/


SNLS First year results with 71 SNIa

with CFHTLS and VLT, Gemini, Keck for spectroscopy

At the end 700 SNIa!

astroph/0510447 to appear in A&A


First results: Cosmological parameter fits

• SNLS first year contours, combined with Baryon oscillation results (Eisenstein et al 2005)


First results: numbers

• For a flat CDM cosmology

• For a flat M,w cosmology,– Combined with Baryonic acoutic oscillation (Eisenstein

2005)

No surprise result! But better control of systematics

M=0.263 +- 0.042 (stat) +- 0.032 (syst)

M= 0.271 +- 0.021 (stat) +- 0.007 (syst)w = -1.023 +- 0.090 (stat) +- 0.054 (syst)


Need for multiprobes to constraint w

Ch. Yèche, A.Ealet, A. Réfrégier, C. Tao, A. Tilquin, J.-M. Virey, and D. Yvon.


Stronger constraints thanks to correlations

40

For m-w0 and for w0-wa, we observe orthogonal correlations between (CMB-WL) and SNIa It allows to break the degeneracies.

Actually we have 9-dim correlations, we gain more than the simple 2-dim overlap! We use the full correlation matrix.


Gravitationnal arcs

Indication of Dark Matter in the

Universe


Weak Lensing effects

Distorsion of background images by foreground matter

Without lensing Lensing effect

A. Réfrégier

“Weak Lensing”

jij

iij zgdz

2

)(Deformation matrix:

Direct measure of mass distribution in the Universe

Other methods measure light distribution

A. Réfrégier


Principles of “Weak Lensing”

Deformation matrix:

Convergence:

Shear

Critical surface density

221

crit

212221121

1 ;)(

lsol

oscrit DD

D

G

c

4

2

22

21

1

1

j

iij

Weak lensing: << 1 (linear approximation)Measure shear and solve for projected mass

“Shear” measurement

Quadrupole Moments : )()(2 xIxwxxxdQ jiij

Ellipticity:2211

122

2211

22111

2,

QQ

Q

QQ

QQ

12 Shear:

12

21

1

1

ij

ii P Relation:


Baryon acoustic oscillations from SDSS LRGs 0.2 < z < 0.5

Acoustic series in P(k) becomes a single peak in (r)!

Pure CDM model has no peak.

Warning: Correlated Error Bars

CDM with baryons is a good fit: 2 = 16.1 with 17 dof.Pure CDM rejected at 2 = 11.7


The Golden age of Cosmology

The Elementary block:

a Galaxy

From COBE to WMAP to Planck Surveyor

HST

map of the sky


Cosmology today … and tomorrow

SNLS, ESSENCE, SNIFS, CSP, … Weak Lensing, CFHTLS, DUNE


Is particle physics useful outside the lab?

• Tune Kamae: Turning the Cosmos into a Particle Physics Lab

OR/AND: using particle physics to understand the X-Cosmos

YES!


2500m2500m

300m300m

50m50m

Electro-opticalElectro-opticalunderwater cableunderwater cable ~40km ~40km

Junction boxJunction box

Readout Cables Readout Cables

Shore stationShore station

anchoranchor

floatfloat

Electronics Containers Electronics Containers

~60m~60mCompass,Compass,tilt metertilt meter

hydrophonehydrophone

Optical M Optical M odulesodules

acoustic detector acoustic detector

Cerenkov Light

track

BioluminescenceK40

Light Sources

p, e+

-

The Golden age of « astro particles » experiments


Neutrino mass from Cosmology?

Data Authors

Mmi

2dFGRS Elgaroy et al. 02 < 1.8 eV

WMAP+2dF+… Spergel et al. 03 < 0.7 eV

WMAP+2dF Hannestad 03 < 1.0 eV

SDSS+WMAP Tegmark et al. 04 < 1.7 eV

WMAP+2dF+SDSS

Crotty et al. 04 < 1.0 eV

Clusters +WMAP Allen et al. 04 0.56+0.30-0.26 eV

All upper limits 95% CL, but different assumed priors !All upper limits 95% CL, but different assumed priors ! Slide from Ofer Lahav


Neutrinos and DE

Cosmology measurementsDark energy, ~ (10-2.5eV)4

Could neutrino energy density scale like dark energy?

Requires neutrino ‘mass’ to increase with scale factor

1998

Atmospheric neutrinos neutrinos oscillate and have mass


Rob Fardon, A.E.Nelson., Neal Weiner; astro-ph/0309800

David B. Kaplan, A.E.Nelson., Neal Weiner; hep-ph/0401099

Kathryn Zurek, hep-ph/0405141

M

llQ

RcRNNQ

m

• Derivative couplings:

CPT violation

Connexions Neutrino mass /DE

-M. Li, X. Wang, B. Feng, X. Zhang, Phys.Rev. D65 (2002) 103511Quintessential Leptogenesis

Xinmin Zhang etal. PRD68, 087301 (2003)

• Direct couplings


Speculations or reality?Future experiments to show

Experimental To Do list (A. Nelson)

Document and consider environment of neutrino path in neutrino oscillation experiments

Consider 13 measurements in reactor experiments with pathlength in air and in rock

Consider environment of neutrinos in direct mass search and 0 measurements

Short baseline experiments to search for heavier sterile neutrinos with small mixing angles; consider varying density of material in neutrino path


The Golden age of Neutrino Physics!

CP Violation in the lepton Sector

Dark Energy


The life of a graduate student in the 70’s?

• Harvard sigma 7 computer – 1966: Scientific Data Systems (SDS)– Computing with cards– One night for a 800 bpi tape and risk of crash VERY high! More thinking before using computers

• Beginning of internet : arpanet use limited• Talks: No Powerpoint• Papers : no archiv, Phys. Rev.

Not flooded with papers sending reprints to requests and libraries

• Largest experiment : CHIO DIS muon ~35 physicistsYou could understand and control all aspects of experimentsMore scientists and less full time managers

• No FPGA (screwdriver and soldering iron electronics)

• Very few women in graduate school: still very few women


How is the life of an experimental particle graduate student in 2005?

• Difficulty in carrying « independent » research in large experimental particle physics groups– Graduate school in particle physics teaches how to be a

good team player

• Long delays between experimental designs and results

• Strong specialization in big teams and pixellisation of responsibility

threat of extinction


And … Physics is exciting!

BUT most graduate students are happy!

So what do we worry about?


Evolving UniverseEvolving PhysicsEvolving People

How to Anticipate Next Golden age ?


Hypothesis: Frontiers of physics evolves

Look at people evolution?

Look at PhD.Thesis topics?

How can that be tested?

Data Not conclusive !

• Low statistics

• Large bias!

• Hidden variables???


Sorry for the bias!

Source: Harvard U. http://www.physics.harvard.edu/academics/phds.html

Did not find online WEB data from BUor any other University


Harvard PhD 1979, 10/20 in particle physics

•AFFLECK, IAN KEITH,. Some Results on Vacuum Decay. (Coleman)

•ALVAREZ, ORLANDO, Conformal Invariance in Quantum Field Theory. (Weinberg)•DAVIS, SAMUEL, Predictions and Limitations of Perturbative QCD. (Georgi)•DE LUCCIA, FRANK JOSEPH, The Fate of the False Vacuum: Induced Decay and Gravitational Effects on Spontaneous Decay. (Coleman)•RICH, JAMES ARNOLD, Trimuon Production by High Energy Neutrinos. (Rubbia)•ROCEK, MARTIN,. Aspects of Spontaneous Symmetry Breakdown of Supersymmetry. (Wu)•SHEIMAN, JOHATHAN LEWIS, Topics in the Theory of Leptoproduction. (Georgi)•SMOLIN, LEE, Studies in Quantum Gravity. (Coleman)•SOBELMAN, GERALD EDWARD, Asymptotic Estimates and Borel Resummation for a Doubly Anharmonic Oscillator. (Coleman)•TAO, CHARLING SUN, The Structure and Formation of Hadrons: An Experiment with a Muon Beam of 219 GeV on a Hydrogen Target. (Wilson)


Harvard PhD 2004 7/21 related particle physics and cosmology

• ABRAHAM, MATHEW CHEERAN, Hot Electron Transpoort and Current Sensing. (Westervelt)

• BOWDEN, NATHANIEL SEAN, Production of Cold Antihydrogen During the Positron Cooling of Antiprotons. (Gabrielse)

• CHANG, SPENCER, Topics in Little Higgs Physics (Georgi)• MOODY, AREEZ MINOO, Thermodynamics of ultracold

singly charged particles. (Heller)• ODOM, BRIAN CARL, Measurement of the Electron g-

Factor in a Sub-Kelvin Cylindrical Cavity. (Gabrielse)• OXLEY, PAUL KEVIN, Production of Slow Antihydrogen

from Cold Antimatter Plasmas. (Gabrielse)• SON, JOHN SANG WON,. Superstring Theory in AdS_3 and

Plane Waves (Minwalla)


Agreement with A. Rosowsky’s proposal!

For graduate students:

better small experiments – atomic physics?


Conclusions

• It was great to be a graduate student in the ’70s– Hope it is still true for today’s students– Certainly is different

• Small experiments are better training grounds to learn independence and experience a full experimental cycle

Is there a future for particle physics?

Pioneering frontiers physics exist and is part of the future


Thank you !


Harvard University PhD 2005 3/11 related to particle physics and

cosmology

NEITZKE, ANDREW M., Toward a Nonperturbative Topological String. (Vafa)SPECK, ANDREW J., Two Techniques Produce Slow Antihydrogen (Gabrielse) THOMPSON, DAVID MATTOON, Holography and Related Topics in String Theory (Strominger)

from physics graduate student in the '70s to observing supernovae today

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