Activities and performance in Europe Performance compared with other regions

1. Theoretical Particle Physics in EuropeNigel Glover (IPPP, Durham)CERN Council Strategy Group Open Symposium LAL Orsay, January 30 2006 Activities and performance in Europe Performance compared with other regions Excellence and diversity within Europe Structural issues for the future

2. Foundations of the Standard Model 1947 electron-muon universality (Pontecorvo) 1948 QED (Feynman, Schwinger, Tomonaga) 1949 Intermediate vector bosons (Lee, Rosenbluth and Yang) 1953 Renormalisation group (Stuckelberg and Gell-Mann) 1954 Non-abelian gauge invariance (Yang and Mills) 1956 Parity (Lee and Yang) 1957 Two component neutrino (Salam, Lee and Yang, Landau) 1958 V-A theory (Feynman and Gell-Mann, Marshak and Sudarshan, Sakurai) 1961 massless bosons from broken global symmetry (Goldstone) 1961 gauge principle for field theory (Salam and Ward) 1961 neutral intermediate vector boson (Glashow) 1963 introduction of Cabbibo angle and hadronic weak currents (Cabbibo) 1964 QFT with SSB, no massless goldstone boson and massive IVB (Higgs, Brout and Englert)

3. Foundations of the Standard Model 1964 quarks as fundamental building blocks (Gell-Mann and Zweig) 1964 color quantum number (Greenberg, Han and Nambu) 1967 electroweak model (Weinberg and Salam) 1967 Feynman rules for Yang-Mills (Faddeev and Popov) 1969 scaling behaviour (Bjorken) 1969 parton model (Feynman) 1970 lepton-quark symmetry and GIM mechanism (Glashow, Iliopoulos and Maiani) 1971 renormalisability of spontaneously broken Yang-Mills theory (‘t Hooft and Veltman) 1973 CP violation in 3 generation model (Kobayashi and Maskawa) 1973 Asymptotic freedom (Gross and Wilczek, Politzer) 1973 QCD Lagrangian (Fritzsch, Gell-Mann and Leutwyler)

4. Foundation of Standard Model • Rapid theoretical progress driven by experimental data • Rapid experimental progress driven by theoretical models • Formulation of Standard Model has led to 30 years of experiments – ISR, PETRA, SppS, TRISTAN, Tevatron, LEP, SLC, HERA,… • The Standard Model is an extremely well tested (if theoretically incomplete) model • There is little doubt that, together with the addition of neutrino masses, it describes all data from the currently accessible regime very well

5. Renormalizability of gauge interactions ‘t Hooft and Veltman, Nucl.Phys.B44:189-213,1972 A new regularization and renormalization procedure is presented. It is particularly well suited for the treatment of gauge theories. The method works for theories that were known to be renormalizable as well as for Yang-Mills type theories. Overlapping divergencies are disentangled. The procedure respects unitarity, causality and allows shifts of integration variables. In non-anomalous cases also Ward identities are satisfied at all stages. It is transparent when anomalies, such as the Bell-Jackiw-Adler anomaly, may occur. [2206 citations] The Nobel Prize in Physics 1999 Gerardus 't HooftMartinus J.G. Veltman "for elucidating the quantum structure of electroweak interactions in physics"

6. Higgs, Phys.Lett.12:132-133,1964 [1037 citations] Phys.Rev.Lett.13:508-509,1964 [757 citations] Brout and Englert, Phys.Rev.Lett.13:321-322,1964 [807 citations] European Physical Society Prize for Particle Physics 1997 Wolf Foundation Prize 2004 Higgs Brout Higgs Englert “for formulating a self-consistent theory of charged massive vector bosons”

7. Supergauge transformations in four dimensions Wess and ZuminoNucl.Phys.B70:39-50,1974 Supergauge transformations are defined in four space-time dimensions. Their commutators are shown to generate γ5 transformations and conformal transformations. Various kinds of multiplets are described and examples of their combinations to new representations are given. The relevance of supergauge transformations for Lagrangian field theory is explained. Finally, the abstract group theoretic structure is discussed.[1274 citations] Supersymmetry Formal development at the time. Has become one of the most eagerly awaited models for the LHC to discover See also Yu.A. Golfand, E.P. Liktman, JETP Lett 13: 323, 1971 D.V. Volkov and V.P.Akulov, JETP Lett 16:438, 1972 D.V. Volkov and V.A. Soroka, JETP Lett 18:312,1973

8. Current status • How does Europe compare to US and rest of world? • In quality? • In volume? • In topic area - hep-th, hep-ph, hep-lat? • In impact on experimental programme? • Try to answer these questions using blind searches in SPIRES • For these purposes use citations as a measure of “quality” • Assign papers to regions based on authors affiliations • Papers with authors from more than one region count more than once • US = USA + Canada • EU = Member states of CERN • RoW = Rest of the World (Russia, Japan, India, Israel, …) WARNING The citation search should be used and interpreted with great care.

9. Top cited papers – pre 1993 • US has a substantial lead • Similar share for all quality cuts indicating level of activity and strength in depth across the regions > 1000 citations > 100 citations > 500 citations

10. 14 papers > 1000, Witten involved in 7, EU in 2 39 papers > 500 – with US involvement in 36! Witten in 11, EU only in 8. Top cited papers – hep-th > 250 citations > 100 citations before 2000 > 50 citations since 2000

11. 4 papers over 1000 (1RS and 3ADD) 33 papers over 500, leading to 25 US entries, 17 EU entries and 3 for RoW Top cited papers – hep-ph > 250 citations > 50 citations since 2000 > 100 citations before 2000

12. 3 papers > 500, all US 21 papers > 250 Japan (RoW) 25 papers > 50 since 2000, 5 papers > 100 before 2000 Top cited papers – hep-lat > 250 citations > 100 citations before 2000 > 50 citations since 2000

13. Top cited papers – pre 1993 • For highest cited papers, CERN largest contributor, although all contribute • For less cited papers, all contribute roughly equally > 1000 citations > 100 citations

14. RoE, CERN and UK strongest Germany improving – AEI Potsdam, Humboldt U Top cited papers – hep-th > 250 citations > 50 citations since 2000 > 100 citations before 2000

15. Much more even distribution across the region CERN (~20%) and DESY (~5%) and (since 2000) IPPP (~5%) Top cited papers – hep-ph > 250 citations > 100 citations before 2000 > 50 citations since 2000

16. Germany clearly dominating – many contributing institutes Many collaborations between D, CH and UK Top cited papers – hep-lat > 100 citations > 100 citations before 2000 > 50 citations since 2000

17. Study in depth • Take specific high cited papers that have influenced the field and examine regional response • Does Europe react quickly enough to lead the field? • AdS/CFT correspondence • Maldacena, hep-th/9711200 [3806] • Large scale extra dimensions • Arkani Hamed, Dimpoulos and Dvali, hep-ph/9803315 [2703] • Braneworlds • Randall and Sundrum, hep-ph/9905221 [2764] • Evidence for oscillation of atmospheric neutrinos • SuperKamiokande, hep-ex/9807003 [2543]

18. The Large N Limit of Superconformal Field Theories and Supergravity Maldacena, hep-th/9711200 World Cites/year Years since publication

19. The Hierarchy Problem and New Dimensions at a Millimeter Arkani Hamed, Dimopoulos and Dvali hep-ph/9803315 World Cites/year Years since publication

20. A Large Mass Hierarchy from a Small Extra Dimension Randall and Sundrum, hep-ph/9905221 World Cites/year Years since publication

21. Evidence for oscillation of atmospheric neutrinos Superkamiokande Coll.,, hep-ex/9807003 World Cites/year Years since publication

22. Quality of response Papers that cite the four standard candles that are themselves topcited > 50 Global Within EU • AdS/CFT correspondence • Maldacena, hep-th/9711200 • [386 out of 3806] • Large scale extra dimensions • Arkani Hamed, Dimpoulos and Dvali, hep-ph/9803315 • [302 out of 2703] • Braneworlds • Randall and Sundrum, hep-ph/9905221 • [498 out of 2764] • Evidence for oscillation of atmospheric neutrinos • SuperKamiokande, hep-ex/9807003 • [273 out of 2543]

23. Impact on the experimental program PYTHIA CTEQ CTEQ MRST CTEQ CTEQ GRV All hep-ph papers with more than 500 citations ranked by number of citations by hep-ex papers Tools have high experimental impact EU is providing its fair share of tools Attendance at dedicated workshops such as RADCOR, is dominated by EU (36/68) cf US (4/68)

24. Top cited hep-ph papers DATE CITATIONS US dominates very top cites (18/20) compared to EU(10/20) but less so in past decade (14/20) compared to (13/20)

25. Impact on the experimental program Monte Carlo programs to be used by ATLAS Clear dominance of EU in providing vital experimental tools

26. Impact on the experimental program Can the citation statistics identify EU strengths in subfields? Look for topcites > 50 to highly cited original paper Asymptotic freedom in parton language, Altarelli and Parisi. Nucl.Phys.B126:298,1977 [3316] The perturbative calculation of jet structure in e+e- annihilation Ellis, Ross and Terrano Nucl.Phys.B178:421,1981 [622] Deep inelastic scattering beyond the leading order in asymptotically free gauge theory Bardeen, Buras, Duke, Muta, Phys.Rev.D18:3998,1978 [1047] One loop corrections for e+e- annihilation into mu+mu- in the Weinberg model Passarino and Veltman Nucl.Phys.B160:151,1979 [1027] QCD QCD QCD Clear evidence of EU dominance EW

27. SUSY phenomenology Nilles, Phys.Rept.110:1,1984 [2940] Haber and Kane, Phys.Rept.117:75,1985 [2874] Flavour Physics Kobayashi and Maskawa, Prog.Theor.Phys.49:652,1973 [4622] Isgur and Wise, Phys.Lett.B232:113,1989 [1472] Hadronic physics Gasser and Leutwyler, Annals Phys.158:142,1984 [1944]

28. neutrino phenomenology Wolfenstein, Phys.Rev. D17.2369, 1978 [2604] Mohapatra and Senjanovic, Phys.Rev.Lett. 44,912,1980 [1590] Astroparticle Jungman, Kamionkowski, Griest Prog.Rept.267.195,1996 [753] WMAP, Astro.J.Suppl.148,175,2003 [3143/719] Heavy Ions Lattice Matsui and Satz, Phys.Lett. B178, 416, 1986 [887] Kogut and Susskind, Phys.Rev. D11, 395, 1975 [1063] Luscher, Phys.Lett.B428:342, 1998 [402]

29. String theory Green and Schwarz, Phys.Lett.B149:117,1984 [1769] Gross, Harvey, Martinec, Rohm, Phys.Rev.Lett.54:502,1985 [1240] Seiberg and Witten, Nucl.Phys.B426:19-52,1994 [1747] Supergravity CFT Witten, Adv.Theor.Math.Phys.2:253,1998 [2645] Freedman,,van Nieuwenhuizen, Ferrara , Phys.Rev.D13:3214,1976 [1240] Belavin, Polyakov and Zamolodchikov , Nucl.Phys.B241:333,1984 [2203]

30. Summary of citations survey • Searching SPIRES reveals the following trends • US dominates in highest topcites • Few individuals with high impact, Witten, … • EU has bigger impact with well cited papers (> 50, > 100) • EU and US have similar speed/volume/quality response to new ideas • EU has excellence in all areas • Compared to US, EU • clear lead in “hardcore” pheno, QCD, EW, hadrons and heavy ions • is very competitive in SUSY pheno, other BSM pheno, CFT, Supergravity, neutrino physics and now lattice, astroparticle physics and flavour physics • Within EUall countries very active • CERN playing a leading role • Germany leads lattice theory • Germany increasing in formal theory – AEI Potsdam • UK increasing in phenomenology – IPPP Durham WARNING The citation search should be used and interpreted with great care.

31. CERN-TH • CERN is the centre of EU excellence for all aspects of particle theory • 13 papers > 1000 and 9 papers > 500 since 1990 • Number of CERN Fellows now with permanent jobs – 70-80% • Visitor programme supports the whole of the EU community and attracts top physicists to Europe • many of the topcited papers are written by visitors • could visitor programme be more focussed? KITP/GGI/INI • CERN Yellow Reports have provided major studies of LEP and LHC physics • Staff retirements provide opportunity for rejuvenation and it is vital to • support the LHC challenge with in house theorists capable of helping experimenters interpret the data • maintain its tradition of excellence in fundamental physics

32. Lattice Gauge Theory QCDOC ApeNEXT • Aim to compute physical quantities with sufficient precision to have impact on experiment • Twin attack • Increased CPU power to increase lattice size/number of ensembles • Currently few Teraflops, aiming for Petaflop • Improved algorithms • Overlap or domain wall fermions – expensive • Wilson fermions – cheap • Staggered fermions – cheapest • Key Questions • Strategy for maintaining investment in CPU • Custom built? Or off-the shelf? • Will B decay constants be computed reliably enough, soon enough?

33. Selected developments • IPPP, Durham – founded 2000 • Galileo Galilei Institute, Florence – inaugural workshop 2005 modelled on KITP 27 Jan 2006

34. EU funding of theoretical physics • In principle, funds to encourage collaboration and mobility within EU but • a lot of time spent preparing applications with very low success rate • emphasis on training rather than on science • PhD recruitment is difficult • Funding is intermittent – 4 years at a time – at best, and too short for sustained development • Key questions • How can we ensure particle theory gets its fair share of funding? • Does funding process reflect the strengths of EU? • Is the funding process sufficiently reliable and transparent? • Is it desirable to have several large networks which by funding restrictions are not allowed to interact? • Would it make more sense to channel funding through CERN? or regional “centres of excellence”?

35. Human Issues • Role of individuals • A few individuals have profoundly shaped our field. As it so happens, many of them work in the US. • Why is this? • Funding? Teaching? Bureaucracy? • Regeneration of the field • Are there enough excellent young people coming through? • Are there enough permanent jobs for these people? • Is the profile of the EU theory community changing with time? • Europe leads in “hardcore” pheno, such as QCD and precision EW. Calculations in these fields can take several man-years. • Do we give enough recognition/support to these fields?

36. Hiring patternsan example – UK recruitment since 2000 Permanent - 30 5 year positions - 16 hep-th 13 hep-ph 14 hep-lat 3 hep-th 9 hep-ph 5 hep-lat 2 US: 3 RoE: 2 RoE: 4 US: 0 UK:6 UK:11 D: 2 D: 7 RoW: 1 I: 2 RoW: 3 I: 5 Sign of a vibrant and re-energised field

37. The future of theory • After the conclusive demonstration in the 1990’s that the SU(3)xSU(2)xU(1) model describes the data very well, a large number of models Beyond the Standard Model have emerged – MSSM and all SUSY variants, Extra Dimensions, Strong Interacting Weak sector, Little Higgs, Split SUSY, … • The LHC data will define the future direction of the field • EU has capacity and expertise to capitalise on developments • Key questions • What is the best way for theorists to interact productively with the experimenters? • Is the theory community fully engaged with and ready for the LHC era?

38. Discussion • What is the best way for theorists to interact productively with the experimenters? • Is the theory community fully engaged with and ready for the LHC era? • Is the age profile of the EU theory community changing with time? • Are the leaders of the field being replaced? • How do we encourage young people to do the vital, but unglamorous detailed calculations needed for experiment? • Is EU disadvantaged by Funding? Teaching? Bureaucracy? • Does having CERN-TH make any difference to EU physics? • What is its most important contribution? • Is EU funding of, for example networks, having a positive or negative effect? • Does funding reflect the strengths of EU? • Is the funding process sufficiently reliable and transparent? • Is there a better way of judging theory success?