Report from the Squark Subgroup

Michael KlasenUniversity of Grenoble I

26 March 2007

26 March 2007 Michael Klasen, Univ. Grenoble I 2

721 Contributions

SUSY Higgs bosons:SUSY H production and FCNC decaySUSY H bs decay and B-physics complementarity

Squark/gaugino production and decayAll NMFV amplitudes, phenomenology for 3rd gen. production

Top squark production and decay:Associated light stop + chargino productionGluino light stop decayLight stop detection with ATLASStop searches with CMS (not received)Stop right-handed sneutrino LSP decay

26 March 2007 Michael Klasen, Univ. Grenoble I 3

2433 ParticipantsM. Beccaria (Lecce)

S. Bejar (Barcelona)G. Bozzi (Karlsruhe)A. de Gouvea (Evanston)B. Fuks (Grenoble)S. Gopalakrishna (Evanston)J. Guasch (Barcelona)T. Hahn (Munich)B. Herrmann (Grenoble)W. Hollik (Munich)J. Illana (Granada)M. Klasen (Grenoble)

S. Kraml (Grenoble & CERN)T. Lari (Milano)G. Macorini (Trieste)

L. Panizzi (Trieste)

S. Penaranda (Valencia)G. Polesello (Pavia)W. Porod (Würzburg)A. Raklev (Bergen & CERN)F. Renard (Montpellier)

J. Sola (Barcelona)A. Tricomi (Catania)C. Verzegnassi (Trieste)

26 March 2007 Michael Klasen, Univ. Grenoble I 4

SUSY Higgs ProductionBejar, Guasch, Sola, hep-ph/0508043

Cross section: HIGLU 2.101 and PPHTT 1.1Leading order onlyRunning mq and s

Default scalesCTEQ4L PDFs

Scan MSSM for max:

26 March 2007 Michael Klasen, Univ. Grenoble I 5

SUSY Higgs Decays (1)Bejar, Guasch, Sola, hep-ph/0508043

Branching ratios ( FCHDECAY):

Partial decay widths: 1-loop SUSY-QCD corrections

FCNC Higgs couplings:

Total decay width: All channels, LO only

Higgs mass / tan : leading mt, mb tan approximation

Constraints on :B(bs) = (2.1 - 4.5) 10-4 (3), same sign as in SM

SUSY-QCD contribution:

26 March 2007 Michael Klasen, Univ. Grenoble I 6

SUSY Higgs Decays (2)Bejar, Guasch, Sola, hep-ph/0508043

h bs [ ] h tc

26 March 2007 Michael Klasen, Univ. Grenoble I 7

SUSY Higgs Decays (3)Hahn, Hollik, Illana, Penaranda, hep-ph/0512315

B(H0, A0 bs):FeynArts/FormCalc/LoopTsAll 1-loop SM/SUSY cont.s

B(b s):NMFV operators:

NLO QCD [Kagan, Neubert]1-loop SUSY contributions

MSSM scenario:

Disfavored by b s

Allowed by b s

26 March 2007 Michael Klasen, Univ. Grenoble I 8

SUSY Higgs Decays (4)Hahn, Hollik, Illana, Penaranda, hep-ph/0512315

26 March 2007 Michael Klasen, Univ. Grenoble I 9

Scans of NMFV Parameter SpaceBozzi, Fuks, Herrmann, MK, LPSC 07-023

Theoretical constraints: ,

Experimental constraints (2):Low energy (FeynHiggs):

[ >0]Dark matter (DarkSUSY):

mSUGRA plane (m1/2 vs. m0): tan = 10, 30, 50

26 March 2007 Michael Klasen, Univ. Grenoble I 10

Proposal of 4 NMFV Benchmark PointsBozzi, Fuks, Herrmann, MK, LPSC 07-023

4 collider-friendly NMFV benchmark points:

-dependence of exp. constraints (point B):

Flavour-decomposition of lighter squarks:

26 March 2007 Michael Klasen, Univ. Grenoble I 11

Squark/Gaugino Production (1)Bozzi, Fuks, Herrmann, MK, LPSC 07-023

Squark mass matrix:

Squared helicity amplitudes:

Gauge boson couplings:

Gluino coupling:

Gaugino couplings:

26 March 2007 Michael Klasen, Univ. Grenoble I 12

Squark/Gaugino Production (2)Bozzi, Fuks, Herrmann, MK, LPSC 07-023

Ex.: (Anti-)squark production

(Anti-)quark cross section:

Form factors:

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Squark/Gaugino Production (3)Bozzi, Fuks, Herrmann, MK, LPSC 07-023

a

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Associated Light Stop + Chargino Production

Beccaria, Macorini, Panizzi, Renard, Verzegnassi, hep-ph/0610075

Motivation for light stop:Electroweak baryogenesismstop < mtop

LO calculation:bg t11

Minimal Flavour ViolationCTEQ6 HQ PDFs

“Experimental” cut:pT > 10 GeV

4 benchmark points:ATLAS data challenge:SU1 (tan= 10), SU6 (50)BMRV light SUSY:LS1 (tan = 10), LS2 (50)

Cross section at threshold:

26 March 2007 Michael Klasen, Univ. Grenoble I 15

Gluino Light Stop Decay (1)Kraml, Raklev, hep-ph/0609293

Majorana gluino, light stop scenario:B(g tt1) ~ 100 % with t bW bl and t1 c1

LHC signature:

Benchmark points:LST1:LST2:

Fast generic LHC-detector simulation: 30 fb-1

Experimental cuts:

26 March 2007 Michael Klasen, Univ. Grenoble I 16

Gluino Light Stop Decay (2)Kraml, Raklev, hep-ph/0609293

26 March 2007 Michael Klasen, Univ. Grenoble I 17

Light Stop Detection with ATLAS (1)Lari, Polesello, ATL-PHYS-CONF-2006-014

Benchmark point:

Signature:t1 b1

± bW±10

B(tt bb+ll+ET) = 4.9%, B(tt bb+l+2jets+ET) = 29 %

HERWIG(t1t1)/PYTHIA(tt)/ALPGEN(Wbb)/ATLFASTExperimental cuts:

26 March 2007 Michael Klasen, Univ. Grenoble I 18

Light Stop Detection with ATLAS (2)Lari, Polesello, ATL-PHYS-CONF-2006-014

26 March 2007 Michael Klasen, Univ. Grenoble I 19

Stop Right-Handed Sneutrino LSP Decay (1)

de Gouvea, Gopalakrishna, Porod, hep-ph/0606296

Right-handed sneutrino LSP:Massive ’s right-handed ’s (see-saw, mR~100 GeV)

SUSY: right-handed sneutrinos; small YN small mixing

NLSP decay into right-handed sneutrino extremly slow

Stop NLSP: t1 ~ tR, no chargino mixing,

Benchmark point:

Signal (PYTHIA):Background (PYTHIA):

26 March 2007 Michael Klasen, Univ. Grenoble I 20

Stop Right-Handed Sneutrino LSP Decay (2)

de Gouvea, Gopalakrishna, Porod, hep-ph/0606296

26 March 2007 Michael Klasen, Univ. Grenoble I 21

SummaryFCNC Higgs decays:

Squark contributions may be much larger than in SMPut constraints on NMFVComplementary to low-energy observables (b s)

Extensive study of squarks/gauginos in NMFV:All squared helicity amplitudes for production and decay knownAllowed regions of NMFV parameter space 4 benchmark pointsLevel reordering flavour changes big cross section variations

(Light) stops:Motivated by cosmologyLarge production cross sectionsGood identification (SS leptons, b-tagging, displaced vertices) Can involve FCNC (t1 c1) sensitive to NMFV