Lynne H. Orr, PIUniversity of Rochester

DOE Progress Report, 2002-03July 23, 2003

Task A: TheoryA1: Phenomenology

Personnel

• FacultyA. DasL. Orr (PI)S. RajeevS. OkuboC.R. Hagen (through '02)

• PostdocsD. Wackeroth (1999-2002)N. Kidonakis (May-Aug.

2002) X. Zhou (Jan.-June 2003)A. Ghinculov (2002-2003)

• Visitors *V.Alves, J.Frenkel,S.KrivonosS.Perez, Z.Popowicz

• Graduate studentsA. AgarwalL. Akant * D. Berdine

(M.S.) J. BoersmaA.

Constandache G. Krishnaswamy * A. MelikyanA. Mitov• Undergraduates *

D. Berdine (2002-'03)

* Supported in part by NSF or other sources.

Introduction• Rochester theory: forefront of particle theory research

mathematical physicsquantum field theory

phenomenology

• Professional activities: highlights-- 52 publications in refereed journals

-- 60 talks (46 invited) at conferences, seminars, colloquia -- 3 books published or forthcoming -- Das elected APS Fellow in 2002

-- Orr: co-convener, Top/QCD Group, American Linear Collider Working Group

-- Okubo: International Advisory Committee, XXIV International Colloquium on Group Theoretical Methods in Physics

• Postdoctoral research associates: Rochester theory postdocs have been very active, and have gone on to excellent positions:

Name Year Current PositionC. Kao 1996 Junior faculty, U. OklahomaS. Pernice 1997 Junior faculty, U. Buenos AiresM. Bisset 1998 Junior faculty, Tsinghua U., BeijingR. Szalapski 1999 Systems Analyst, Avanti SystemsO. Kong 1999 Junior faculty, Nat'l Central U., TaiwanV. John 2000 FinanceG. Corcella 2001 Research Assoc., CERND. Wackeroth 2002 Junior faculty, SUNY BuffaloA. Ghinculov 2003 Merill Lynch

• Graduate students: Among finest in the department, including -- Okubo prize winners (best prelim performance)-- Sproull fellowship (university-wide competition)

-- Prestigious subsequent positions (next slide)• Undergraduate students: Strong history of participation

-- APS Apker Prize for best thesis (Krishnaswami)-- Graduate schools include Chicago, UC Berkeley,

Rochester

Alexander Mitov 2003 L. Orr RA, University of HawaiiLevent Akant 2003 S. Rajeev RA, Feza Gursey Institute, Turkey

C. Richard HagenQuantum Field Theory

• Hagen's research was supported by this grant through 2002. No further support is requested.

• Research topics:– Galilean relativity in field theory– Unification of 2-D soluble vector coupling models– Chern-Simons theory in 2+1 D and Aharonv-Bohm effect– Finite Temperature field theory

• Retired from teaching, but still active in research (8 papers in 2002-03). Receives nominal support from Task A.

• Research: studies mathematical symmetries with aim of physics applications– Non-asssociative algebras– Exceptional Lie algebras– Global symmetires of time-independent Schrodinger

equations• Linear, inverse quadratic, quadratic potentials

Susumu OkuboMathematical Physics

Ashok DasM Theory, Finite Temperature Field

Theory, Integrable Models

• Personnel:– Postdoc: X. Zhou– Visitors: V.Alves, J.Frenkel,S.Krivonos, S.Perez, Z.Popowicz– Graduate students: A. Constandache (arrived 1998), A.

Melikyan (1999)• Professional Activities

– Elected APS Fellow, 2002, for contributions to supergravity, integrable models, and finite temperature field theory

– 23 refereed publications– 3 books published or forthcoming– Many invited talks and lectures, including Brazil, Chile,

Poland, India, US– Scientific Organizing Committee, Conference on

Symmetries, Dubna, July 2003

Ashok Das: Research

• Integrable modelsThis class of exactly solvable systems appears in string theory,

M theory, and topological field theories. Das has studied these systems, with results including

• construction and characterization of conserved charges (resulting from symmetries) that do not arise from the conventional description

• Finite temperature field theoryFinite temperature field theory is needed to describe phase

transitions, including the electroweak phase transition in the early universe and the transition from ordinary matter to quark-gluon plasma.

Das continues to do seminal work in this field:• He wrote the book: Field Theories at Finite Temperature• Screening length and magnetic mass in Chern-Simons theories• Non-commutative theories• Light-front theories

Ashok Das: Research, continued

• M Theory, non-commutative field theories, extra large dimensions• M(embrane) theory is our latest candidate for a Theory of

Everything. Das has made significant progress in showing how to quantize a particular class of membranes.

• Non-commutative theories are also becoming important, and Das has shown how to calculate physical quantities (e.g. photon self-energy) in these theories

• Extra large dimensions could provide the key to solving the electroweak hierarchy problem.

Das has shown how a systematic study of the radion -- a new degree of freedom that arises in the Randall-Sundrum version of these models -- can be carried out from a geometrical point of view

Lynne H. OrrCollider Phenomenology, Radiative

Corrections• Personnel:

– Postdocs: D. Wackeroth, A. Ghinculov– Postodoctoral visitor: N. Kidonakis– Graduate students: D. Berdine (MS), J. Boersma (arrived 2002),

A. Mitov (1999; Ph.D. 2003)– Undergraduate student: D. Berdine (2002-03)

• Professional Activities– Co-convener, Top/QCD group, American Linear Collider Working

Group– APS J.J. Sakurai Prize selection committee– 8 refereed publications– 20 presenations, including

• Conference Summary (Theory), 2003 QCD Rencontres de Moriond, Les Arcs, France

• Plenary talk, 2002 Phenomenology Symposium, Madison, WI• Plenary talk, Loopfest I, Brookhaven National Lab, June 2003• 8 talks by graduate students; 3 talks by undergraduate students

– Activities to encourage recruitment and retention of women in physics, including co-direction of Physics Undergraduate Teaching Internship Program

Lynne H. Orr: ResearchMotivation: What lies beyond the Standard Model and

what is the key to electroweak symmetry breaking? How can we test the SM and answer these questions experimentally?

•Top quark physicsTop phenomenology at present and future colliders. Synergy with experimental group.• Systematic study of QCD effects in top quark physics

• Tevatron, LHC: gluon radiation and mass reconstruction• Future linear e+e- collider • In progress: combine QCD and electroweak corrections (for e+e) to obtain full NLO calculation of top production and decay

C.Macesanu and L.Orr

e+e- -> t t

--- LO--- on-shell NLO--- off-shell NLO

Lynne H. Orr: Research, continued• QCD corrections to top-Higgs associated production

• Tevatron: postdoc D. Wackeroth (and Reina, Dawson)• LHC: Orr, Wackeroth, Dawson, Reina

Lynne H. Orr: Research, continued

• QCD corrections to top-Higgs associated production, continued

Lynne H. Orr: Research, continued

• QCD corrections to top-Higgs associated production, continued

From S. Dawson, L. Orr, L. Reina, D. Wackeroth, Phys.Rev. D67:071503,2003

Lynne H. Orr: Research, continued

• QCD corrections to top-Higgs associated production, continued

In progress and planned: distributions, soft gluon resummation• SupersymmetrySUSY is a leading candidate for the explanation of electroweak symmetry breaking.• MSSM and general two-Higgs double model: with C. Kao, Orr has studied production of ZA at the LHC:• R-parity violating models: past work

D. Wackeroth, postdoc:

• Precision electroweak physics RacoonWW: Electroweak radiative corrections to WW production at LEP2

http://ltpth.web.psi.ch/racoonww/racoonww.html

A. Ghinculov, postdoc:

• Two-loop radiative corrections• Rare B decays:

Near completion!

Sarada RajeevNonperturbative Field Theory,

Mathematical Physics

• Personnel:– Graduate students: A. Agarwal (arrived 1999), L. Akant

(1997; Ph.D. 2003), G. Krishnaswami (1999)

• Professional Activities– 7 refereed publications– 16 talks by group members, including many international

invited presentations, including • Plenary talk at 2003 MRST conference• Talks by graduate students

– Advisory committee, Conference on Spacetime and Fundamental Interactions, Salerno, Italy

– Organizer, Rochester mathematical physics discussion group

Sarada Rajeev: ResearchUnderlying motivation: How to describe Yang-Mills theory (e.g. the

gauge theory of the Standard Model) even in the nonperturbative regime? In particular, can we have a quantum theory of hadrons?

Approach: Simplify the problem: reduce the dimensionality of space-time, take the large-N limit, work with matrix models. Extract the essential features and apply to the more difficult problem

• Hadrons in 2 space-time dimensions

Rajeev's earlier Skyrme theory of hadrons in 2-D: gluon degrees of freedom can be neglected. Recently: apply to Deep Inelastic Scattering to obtain parton momentum distribution functions from first principles.

G.Krishnaswami and S.Rajeev, Phys. Lett. B441 (1998) 429.

Valence quark parton density function (`DATA’=MRS fit)

Sarada Rajeev: Research, continued

• Yang-Mills in 2+1 Dimensions: Find a general theory of hadrons and reproduce the hadron spectrum

• Loop space formulation of gauge theories:Hadron theory: dynamical variables = closed loops in spacetime; new

mathematical ideas needed. Connections to modern mathematical ideas.

• Large N limit as new classical limit:SU(3) -> SU(N), N large: quantum fluctuations die off as 1/NGet classical limit with large N. Rajeev has studied this limit and is wrtiting a book compiling

his work.

• Matrix models:Non-commutative geometry and connections to probability

theory

Sources of Support

• The DOE theory core budget provides the primary support for the theory group, including graduate students, postdocs, administrative personnel, faculty summer, travel, materials, supplies, computing

• Task A1 (2001-02) was supported through the Linear Collider Detector studies

Additional support:• Orr's NSF Career Award (1996-2000)• Das's NSF US/Brazil Cooperative Research Grant• Physics Dept. NSF Research Experience for

Undergraduates• University support, including fellowships and tuition

waivers Krishnaswami: Sproull Graduate Fellowship