Split Supersymmetry: Signatures of Long-Lived Gluinos Intro to Split SUSY Long-Lived LHC Long-Lived Gluinos in Cosmic Rays JLH, Lillie, Masip, Rizzo hep-ph/ SUSY05 Durham J. Hewett

Split SUSY Intro & Philosophy –See Savas Dimopoulos, Thurs plenary Arkani-Hamed, Dimopoulos hep-ph/ Giudice, Romanino hep-ph/ Split SUSY Collider Phenomenology –See SUSY/Higgs Parallel, Friday afternoon Numerous authors & papers! Split SUSY Dark Matter –See Astro Parallel, Wed afternoon Numerous authors & papers!

Split Supersymmetry: Philosophy SUSY is irrelevant to the hierarchy problem –Cosmological constant problem suggests fine-tuning mechanism  may also apply to the gauge hierarchy Break SUSY at the GUT scale –Scalars become ultra-heavy (except 1 light Higgs): m S ~ GeV –Fermions protected by chiral symmetry Phenomenological Successes: –Retain gauge coupling unification –Higgs mass predicted to be `heavier’: m H ~ GeV –Flavor & CP problems are automatically solved –Proton decay is delayed (occurs via dimension-6 operator) Collider signatures & Dark Matter implications substantially different!

This ties into the Landscape picture Courtesy of Linde

Fine-tuning does occur in nature 2001 solar eclipse as viewed from Africa

Whether you buy into this program or not, it behooves us to examine the collider signals of Split SUSY We don’t know what the LHC is going to discover and we need to be prepared!

Gauge Coupling Unification: (See Dimopoulos) 1 TeV 1-loop Split 1-loop m S = 10 9 GeV Arkani-Hamed, Dimopoulos hep-ph/

Higgs Mass Prediction: (See Dimopoulos) m H = GeV for m S > 10 6 GeV Measurement of gaugino Yukawas determines SUSY breaking scale Arvanitaki, Davis, Graham, Wacker hep-ph/ Higgs 1-loop tan  = 50 1 Error bands reflect m t &  s errors

LSP (  1 0 ) is still dark matter candidate (See Dimopoulos) 1010 1010 1010 1010 h f,V f,V (*) - V V (*) Main annihilation channels : No scalar exchange depends on fewer parameters Points which satisfy WMAP relic abundance constraint Pierce, hep-ph/ co-annihilation graphs  very efficient!!

Collider Phenomenology: EW Gauginos Produced in pairs via Drell-Yan  1 0 is LSP Only open decay channel :   (  2 0 ) W  (Z) 1010 No cascade decays! Tri-lepton signature sill valid, except Gaugino couplings (at the TeV scale) are smaller than those in MSSM GUT tests require accurate coupling ILC

Collider Phenomenology: Gluinos Pair produced via strong interactions as usual Gluinos are long-lived No MET signature Interesting detector signatures g ~ q ~ q q 1010 Gluino lifetime: ranges from ps to age of the universe for TeV-scale gluinos ( Cosmological constraints ) JLH, Lillie, Masip, Rizzo hep-ph/ Gluinos as LSP: Baer etal 1998  ~ ps, decays in vertex detector ps <  < 100 ns, decays in detector  > s, decays outside detector  bulk of parameter space!

Gluino Hadronization and Fragmentation Gluino hadronizes into color singlet R-hadron R is neutral: energy loss via hadronic collisions as it propagates through detector R is charged: energy loss via hadronic interactions and ionization R flips sign: hadronic interactions can change charge of R, can be alternately charged and neutral!  ionization tracks may stop & start! Fragmentation is uncertain: slight preference for neutral R-hadrons Prob < Prob m - m > m 

Energy Loss in the Detector Hadronic Interactions: RN  RX –model with constant differential or triple pomeron –deposits few 100 MeV per interaction Mean interaction length: ~ 19 cm in Fe 100 GeV R with E = 400 GeV, deposits at most 6.4 GeV in CDF Ionization: Bethe-Bloch Eqn –sizeable energy loss for slow moving R-hadrons –fast moving R-hadron deposits ~ 1.5 GeV ~ k  k typically ~ ( GeV) Either case: amount of energy deposition may escape triggers! Interactions due to light constituents  energy loss  E ~ 

Average speed of Tevatron Case 1: constant differential Case 2: triple pomeron

Gluino Production:  = 0.2 m gluino as suggested by NLO

Searches: 1.Stable, neutral R-hadron: most challenging case! Energy loss via hadronic ints unobservable Consider Gluino pair + jet production Trigger on high p T jet Since scalars decouple, use QQ + jet production Monojet Searches: CDF: One central jet E T > 80 GeV MET > 80 GeV Run I 284 events observed 274  16 expected New Physics < 62 events M gluino > 170 GeV 215 GeV (scaled Run II with 1 fb -1 ) LHC: one central jet E T > 750 GeV MET > 750 GeV expect ~ 4200 bckgnd events M gluino > 1.1 TeV for 100 fb -1

Gluino pair + jet cross section Tevatron Run II (1 fb -1 ) LHC At LO with several renormalization scales

2.Stable, charged R-hadrons: –time of flight for slow moving (relative to  = 1)  ranges from 0.8 (m = 200 GeV) to 0.4 (m = 500 Tevatron –high ionization energy loss for fast moving charged R-hadrons can be tracked as they traverse the detector –Consider only gluino pair production w/o bremstrahlung –CDF: Heavy charged stable Particle search yields m gluino > 270 GeV (Run I) 430 GeV (Run II with 2 fb -1 ) Ionization loss (dE/dx) for  ≤ 0.85: M gluino > 300 GeV (Run I) LHC: Scale CDF results m gluino > 2.4 TeV

3.Alternating sign R-hadrons (flippers) –Re-fragmentation after every hadronic interaction –highly model dependent!!! –worst case scenario is monojet signature from 100% neutral R-hadrons –Signature: off-line analysis of monojet signal reveal charged tracks that stop & start  puffs of ionization energy deposition!

R-hadrons in Cosmic rays: Signatures in IceCube p+N  gluino pairs R-hadrons form interact with nucleons in atmosphere & ice Showering R-hadrons very energetic! Deposit ~ TeV in atmosphere Deposit ~ 40 TeV in IceCube

Number of events IceCube Not competitive with colliders

Summary Split SUSY predicts novel collider (& cosmological) signatures Gaugino decays differ substantially from MSSM Need to re-examine gaugino searches Worst case scenario: R-hadron neutral & stable –Tevatron search reach up to m g ~ 270 GeV –LHC search reach up to m g ~ 1 TeV Search reach extended if R-hadrons charged Cosmic ray signals not quite competitive with colliders ~ ~