Collider signatures of gravitino dark matter with a sneutrino NLSP Euro-GDR SUSY, 12-14 Nov 2007, Brussels, Belgium Collider signatures of gravitino dark matter with a sneutrino NLSP Sabine Kraml LPSC Grenoble based on: L. Covi, SK, JHEP08(2007)015 D.T. Nhung, SK, in preparation

Gravitino DM with sneutrino NLSP Contents Introduction no-scale SUSY with NUHM RGE analysis of mass hierarchies Sneutrino NLSP region (with gravitino LSP) Mass patterns 3-body decays of sleptons Impact on LHC cascade decays Gravitino relic density and BBN Conclusions S. Kraml Gravitino DM with sneutrino NLSP

Higgs-exempt no-scale supersymmetry Evans, Morrissey, Wells ‘06 Higgs-exempt no-scale supersymmetry Vanishing scalar soft terms at M(GUT) Free parameters Possible in GUTs with sequestered scalar sector, gaugino mediation, conformal dynamics,…. Buchmüller, Kersten, Schmidt-Hoberg ‘05 Buchmüller, Covi, Kersten, Schmidt-Hoberg ‘06 S. Kraml Gravitino DM with sneutrino NLSP

Gaugino-mediated SUSY breaking Kaplan, Kribs, Schmaltz ‘99 Chacko, Luty, Nelson, Ponton ‘99 Gaugino-mediated SUSY breaking SUSY breaking occurs through a superfield S localized on a 4-dim brane in a higher-dim theory. Gauge and Higgs superfields live in the bulk and couple directly to S  gaugino and Higgs fields acquire soft masses at tree level Squarks and sleptons are confined to a brane w/o direct coupling to S  no-scale boundary conditions hidden visible SUSY MSSM gauge & Higgs superfields Buchmüller, et al. S. Kraml Gravitino DM with sneutrino NLSP

Gravitino DM with sneutrino NLSP RGE analysis 1-loop running of scalar mass parameters Compare with gaugino mass parameters SGUT  0: mE  M1  mL SGUT  0: mL  M1  mE S. Kraml Gravitino DM with sneutrino NLSP

Gravitino DM with sneutrino NLSP Gaugino mediation = SGUT Masses computed with SOFTSUSY S. Kraml Gravitino DM with sneutrino NLSP

Gravitino DM with sneutrino NLSP Evans, Morrissey, Wells ‘06 Gravitino LSP S. Kraml Gravitino DM with sneutrino NLSP

-Sneutrino NLSP region (assuming a gravitino LSP)

 NLSP region: peculiar mass spectra L. Covi, SK ‘07  NLSP region: peculiar mass spectra ~ A: B: C: B,C Visible 1 decays, 3-body decays of sleptons dashed blue lines: sneutrino-stau mass difference (small!) S. Kraml Gravitino DM with sneutrino NLSP

Gravitino DM with sneutrino NLSP dominant S. Kraml Gravitino DM with sneutrino NLSP

LHC cascade decays m of few GeV  soft decay products 99% 33% 32% 19% m of few GeV  soft decay products need to be able to measure low-pT e and  S. Kraml Gravitino DM with sneutrino NLSP

LHC cascade decays -cont- ~70% Last step invisible, looks like 1 LSP 32% 32% 2 SFOS leptons + 1  32% 32% may fake LFV? 60% 30%  NB: in mSUGRA this would be a right slepton S. Kraml Gravitino DM with sneutrino NLSP

Gravitino DM with sneutrino NLSP LHC cascade decays -cont2- S. Kraml Gravitino DM with sneutrino NLSP

Gravitino DM with sneutrino NLSP D.T. Nhung, SK, in prep. Slepton 3-body decays   Computed all slepton 3-body decays into other sleptons and implemented them in SDECAY. (NB: discussed within GMSB by Ambrosanio et al ‘97) S. Kraml Gravitino DM with sneutrino NLSP

Gravitino relic density and BBN constraints NB: gaugino mediation favours gravitino mass of O(GeV)

Gravitino relic density Non-thermal production (superWIMP effect)  negligible for sneutrino NLSP: Thermal production S. Kraml Gravitino DM with sneutrino NLSP

Gravitino DM with sneutrino NLSP Kanzaki, Kawasaki, Kohri, Moroi ‘06 BBN constraints Stem from (hadronic) 3- and 4-body sneutrino decays into the gravitino * * With this approx., no constraint for m < 300 GeV ~ S. Kraml Gravitino DM with sneutrino NLSP

BBN constraints -cont- L. Covi, SK ‘07 BBN constraints -cont- Complete calculation of Y with microMEGAs gives a bit stronger bounds than estimate by Kanzaki et al. But still much less constrained than stau NLSP. S. Kraml Gravitino DM with sneutrino NLSP

Gravitino DM with sneutrino NLSP Conclusions In models with non-universal Higgs masses and large S<0, left-chiral sleptons can be lighter than the 10 The gravitino is a natural dark matter candidate in such a case. Sneutrino NLSP much less constrained by BBN than stau. LHC cascades characterized by 3-body slepton decays at the end of the chain  mixed flavors, soft leptons  challenging ILC analysis also complicated by 3-body decays (e.g., selectron-pair production leading to e  Emiss signature) Dedicated experimental analysis to establish LHC/ILC potential for such a scenario would be very interesting. S. Kraml Gravitino DM with sneutrino NLSP