Fri. Sept. 23, 2005 RECFA at NIKHEF 1

Theoretical physics

Eric Laenen

NIKHEF and Utrecht University

Fri. Sept. 23, 2005 RECFA at NIKHEF 2

Dutch theory groups

Free U. of AmsterdamUtrecht U.

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U. of Amsterdam

Free U., Amsterdam

NIKHEF

Leiden U.

Radboud (Nijmegen) U.

Groningen U.

Utrecht U.

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Groningen (RuG)M. de Roo [Strings & quantum gravity]E. Bergshoeff [Strings & quantum gravity]E. Pallante [Lattice field theory][50%]

6 Ph.D.’s, 1 Postdoc8 papers in 04

Funding: RuG, FOM, EU networks, INTAS, Nordic Network

Collaborations: KVI, Utrecht, Cambridge, Kings’s Coll, Brussels, Leuven, Stanford

Noteworthy:Pallante starts particle/latticgroup, using

LOFAR BlueGene/L computerString theory cosmology focus

Groningen (KVI)R. Timmermans [Baryon interactions, chiral PT,

Atomic P violation]

O. Scholten [Nucl. Phys., HE Cosmic rays]

2 Ph.D, 1 Postdoc

11 papers in 04

Funding: FOM, RuG, EU networks

Collaborations: VU, Nijmegen, Gent, Osaka,..

Noteworthy:

Workshops at Trento, Seattle

Close contact with TRImP, GSI

More ambitions towards astroparticle physics

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Free University (VU) AmsterdamP. Mulders [QCD spin ph., proton structure]

D. Boer [QCD spin ph., phase structure]

B. Bakker [Lightfront field th., hadr. Struct.]

[40 %]

3 to 4 Ph.D.’s, 1 to 2 Postdocs

8 papers in 04

Funding: VU, FOM, EU

Collaborations: KVI, Torino, Regensburg, BNL, Imperial, Heidelberg

Noteworthy:

Joint theory Master’s program with UvA

Good contacts with NIKHEF theory, VU Exp. (Babar/LHCb,HERMES, LISA)

Leiden UniversityA. Achucarro [Topological/NP field theory and

cosmology]

P. van Baal [NP Yang-Mills, lattice, HiSparc]

W. Van Neerven [pert. QCD at colliders]

Lorentz professor [Susskind, Wilczek, Kadanoff]

[30%]

3 to 5 Ph.D’s, 3 to 4 Postdocs

19 papers in 04

Funding: UL, FOM, NOW, EU-RTN, ESF, other countries

Collaborations: NIKHEF, Cambridge, Sussex, Berkeley, Madrid, Trinity, Princeton

Noteworthy:

Workshops at Lorentz Center

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UtrechtG. ‘t Hooft [quantum physics]B. de Wit [strings & quantum gravity]R. Loll [quantum gravity]J. Ambjorn [quantum gravity]T. Prokopec [cosmology]G. Aryutanov [strings & quantum gravity ]S. Vandoren [strings & quantum gravity]K. Peeters (‘06) [strings & quantum gravity]Kramers professor [Ashtekar,..]

[60%]

7 Ph.D’s, 7 Postdocs33 papers in 04

Funding: UU, FOM, NWO, KNAW, EU, INTAS

Collaborations: UvA, Groningen, many abroad

Noteworthy:Summer school, well-attended Master’s

program

Nijmegen (Radboud U.)R. Kleiss [collider physics, QFT methods]

W. Beenakker [(B)SM at colliders, EW]

T. Rijken [Baryon interactions]

3 Ph.D.’s

8 papers

Funding: RU, FOM, EU

Collaborations: Athens, DESY, PSI, Osaka

Noteworthy:

Good contacts with NIKHEF theory, and Nijmegen HEP [ATLAS/D0] and PA [HiSParc/NAHSA]

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University of Amsterdam (UvA)R, Dijkgraaf [Strings & quant. gravity, math.]J. de Boer [Strings & quant. gravity]E. Verlinde [Strings & quant. Gravity]F..Bais [Strings & topol. FT]J. Smit [Lattice FT, cosmology]K. Skenderis [Strings & quant. Gravity]M. Taylor-Robinson [Strings & quant. Gravity]K. Schalm [Strings & quant. Gravity]C. van Weert [Thermal field theory][50%]

10 Ph.D.’s, 7 Postdocs36 papers in 04

Funding: UvA, FOM, NWO, EUCollaborations: UU,NIKHEF,NBI, Harvard,

CERN, Princeton, Caltech,…

Noteworthy:Spinoza prize for Dijkgraaf; Highly acclaimed annual summer workshop

on StringsOutreach

NIKHEFJ. Koch [Fin. T. lattice QCD, RHIC phys.]

B. Schellekens [Strings & quant. gravity]

J.W. van Holten [SUSY, Cosmol., HiSPARC]

J. Vemaseren [high order pQCD, FORM]

E. Laenen [pert. QCD, heavy quark physics]

5 Ph.D’s, 2 Postdocs

13 papers in 04

Funding: FOM, UvA, UU

Collaborations: DESY, Durham, Bielefeld, CERN, Torino,Chennai,Madrid

Noteworthy:

Host of National Seminar

Close contact with NIKHEF experiments

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Nikhef theory group

Activities• Pursuit of active, wide-ranging research program• Close interaction with NIKHEF experiments (analyses, Ph.D.’s, ICHEP’02, topical lectures)• Introduce new theoretical developments to NIKHEF• Training Master’s, Ph.D. students and postdocs• Members have professorships at 4 Universities teaching / exposing students to NIKHEF research

Future funding• New FOM program with University groups (2007 ?)• EU-RTN networks, NWO, small FOM grants…

Special expertise: FORM (Jos Vermaseren)

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Permanent staff/topic in 5 years from now

Strings & quantum gravity [14]

Groningen (2)

Utrecht (5)

U. of Amsterdam (6)

NIKHEF (1)

Lattice & non-pert. FT [4]

Groningen (1)

KVI-Groningen (2)

Leiden (1)

Cosmology & PA [3]

Leiden (1)

Utrecht (1)

NIKHEF (1)

High-energy collider physics [6]

NIKHEF (2)

Nijmegen (2)

Free U. (2)

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Theory Ph.D students and postdocs

Ph.D. students• Total: 40-50, more than half from NL• 60% continue to postdocs• Education through Dutch Research School for

Theoretical Physics

Postdocs• About 20-25• Mostly non-Dutch

Sept. 23, 2005 Theoretical physics 10

Dutch Research School for Theoretical Physics

• Offers joint program for education of TH Ph.D. students at 6 universities + NIKHEF via advanced courses

• Two themes: 1. Quantum Field Theory and Elementary Particles 2. Condensed Matter and Statistical Physics• Organizes biannual 2-day symposium with both themes• Organizes yearly Winter Schools in Nijmegen. 2 weeks, 4 lecturers, 25-30 1st & 2nd year Ph.D. students. E.g.

2005:

G. ‘t Hooft: Advanced quantum field theoryE. Verlinde: String theory and black holesS. Weinzierl: Methods in higher order perturbation theoryT. Prokopec: Cosmology

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Key research topicsStrings & quantum gravityHolography/AdS-CFTBlack hole entropyTopological stringsStandard Model from stringsString cosmology

Lattice & non-pert. field theory

CaloronsFinite T latticeLight-front and effective theories

Cosmology & PABaryogenesis

Domain walls

Cosmic scalar fieds

High-energy collider physics Higgs + t-tbar production

Jet production

Color glass

Spin physics

Resummation, top quark physics

on latticeI 1

2, '/

Fri. Sept. 23, 2005 RECFA at NIKHEF 12

Theory and Experiment

QCD - ATLAS/D0, HERAStructure functions(Next-to-leading order) Monte Carlo’sJet physicsResummation

EW - LHC, ILC, LEPRadiative correctionsTop quark physicsHiggs physics

PA - Antares/KM3NetCosmic neutrinosGravitational wavesCosmic Rays

Spin - Hermes/CompassTransversitySpin structure functions

Heavy Ions - Alice/STARFinite T latticeColor glass condensate

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Two physics topics

1. Quantum gravity via causal dynamical triangulations [Loll, Ambjorn, ..] (Utrecht)

2. 3-loop QCD splitting functions [Vermaseren, Moch, Vogt] (NIKHEF)

Fri. Sept. 23, 2005 RECFA at NIKHEF 14

The Universe from Scratch[Loll, Jurkiewicz, Ambjorn]

• Minimalist approach to quantum gravity• No strings etc assumed

Premise• At very short distances, spacetime fluctuates wildly• No background spacetime; “the stage itself becomes actor”

Sanity conditions• Wild geometries at short distance ok• Einstein GR at larger distance

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Tools: Path Integral

Path integral

Z(gi ,g f ) eiSgravity ( path)

paths (i f )

• Genuinely non-perturbative• Most paths very weird• Magic of PI: true quantum physics due to superposition• Sum over suitable class of geometries• Sum eventually done on computer

Fri. Sept. 23, 2005 RECFA at NIKHEF 16

Tools: Triangulation of spacetimeRepresent each spacetime in sum by piecewise flat geometries

Curvature located at vertices

Triangles • Edges all common length• Sum over gluings 4-simplices

Fri. Sept. 23, 2005 RECFA at NIKHEF 17

Inputs

Sgravity 1

GNCurvature(T ) Volume(T )

Usual Euclidean version produced weirdspacetimes, with strange (Hausdorff) dimensions. Dimensionis dynamical quantity!

eiS e S

Key condition: causal dynamicaltriangulations (microcausality)!

Fri. Sept. 23, 2005 RECFA at NIKHEF 18

ResultsDimension of spacetime• Hausdorff dimension: 4!• Dimension (diffusion) at large scale• Dimension at short distance• Glimpse of spacetime near Planck length?

Quantum cosmologyScale factor a(t) of UniverseCDT allows expansion

Fri. Sept. 23, 2005 RECFA at NIKHEF 19

Second order parton evolution kernels[Vermaseren, Moch, Vogt]

• Opens gate to 2nd order perturbation theory at LHC• Marvellous computer algebra tool: FORM • 3-loop QCD. “Calculation of the decade”

Quick acclaim:

• 200 citations after 1.5 year• selected Top Article in Nuclear Physics

Earlier, the 4-loop QCD function..

1, 2, 3 & 4-loop calculators

FORMauthor

# colors in QCD (strong interaction)(3: “red”, “green” & “blue”)

# quark flavors(6: u-, d-, c-, s-, t- & b-quarks)

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Hadronic cross sections and pQCD

Fri. Sept. 23, 2005 RECFA at NIKHEF 22

theor PDF(x1, x2 ) hardTheoretical cross section:

Input: • hard scattering cross section calculate in perturbative QCD• parton distribution functions PDF determine from benchmark data (DIS)

hard

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Evolution kernels

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How well do we know the PDF’s?

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Evolution kernels in QCD perturbation theory

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Heroic effort

• 20 Man-years• 1M lines of FORM code• Several CPU years• 10K diagrams, 100K integrals

Scale dependence at NNLOmuch better…

First NNLO PDF sets appearing

Fri. Sept. 23, 2005 RECFA at NIKHEF 29

A corolllary (Moch, Vogt)..

Fri. Sept. 23, 2005 RECFA at NIKHEF 30

Prospects for Dutch theoretical physics

Staff• A number of retirements coming up. Some positions prefilled.• Strings & quantum gravity effort strong, young• Cosmology & astroparticle physics smallish• Phenomenology not too large, decreasing.Funding of Ph.D.’s and Postdocs• University funding: under pressure• Present: 3 FOM-TH programs: Universities (<2007), NIKHEF

(<2007), Strings (<2009): also under pressure• Very important: new FOM-TH proposal, in preparation.

Universities + NIKHEF • Increasingly look toward European funding