status of beyond the sm searches - university of...

Status of Beyond the SM Searches

maria spiropuluCERN-PHYSICS

<[email protected]>

Vienna, July 16, 2004

Status of Beyond SM Searches [email protected] [1]

[...] @ Colliders and Mostly with Data

There is also ‘”towards BSM” implications/results from

• Neutrinos

• Astrophysical Observations, UHECR, CMB

• B-Factories

• Macroscopic Gravity Experiments

• &tc

that we will not discuss here

Physics at LHC, Vienna 04


The High Energy Data We Have

• Tevatron

– pp, ∼120 pb−1 at√

s = 1.8 TeV– < xxx pb−1 at

√s = 1.96 TeV

• HERA

– ep at√

s = 320 GeV ∼ 120 pb−1 (2001)

• LEP

– ee at√

s up to 209 GeV ∼ 1 fb−1



Our High Energy Delinquencies Today

• Tevatron

– top quark mass and tt cross section– “superjet” events vis a vis b-tagging

• HERA

– H1 vs ZEUS - events with large missing ET and a lepton

• LEP

– ???



PDG the last 10 years on BSM Searches

• Free Quarks - discarded in 1996

• Magnetic Monopole

• SUSY

• Technicolor - included in 2001

• Quark and Lepton Compositeness

• Extra Dimensions - included in 2002

• Other Stable Particles - renamed WIMPS and Other Particles in 1997



PDG the last 10 years on BSM Searches

1=Monopoles, 2=SUSY, 3=Technicolor 4=Compositeness 5=EDs 6=WIMPS



Lykken’s list for pheno BSM, BSUSY

• U(1)′

• little higgs

• EWSB or SUSY breaking from extra dimensional boundary effects

• radions, branons

• black holes, string balls

• flavor and EDs

• leptoquarks



Initial Remarks

• most all can be motivated from one kind or another of Extra Dimensionsand/or SUSY

• there is loose or strict dualities between the BSM models → the finalstates/data signatures can be the same → the characterization of anexcess or a deviation could be in the fine details → dig out all theinformation out of an event (there is millions of channels in the moderndetectors giving you kinematics, topology, everything)

• From the “analysing the data” point of view, i think one needs to knowthe qualitative and quantitave differences in the predictions of the modelsand not exactly the models → this leads to the disentangling efforts today



(is it UED or is it SUSY, is it a Z ′ or is it an RS graviton mode? is it amonopole or a light gluino? etc)

• all data that we have today point to the fact that there is somethingmore but that it is rather tricky to say what.

• in HEP today when we talk about Beyond the Standard Model (includingSUSY) we talk about data at the edge or tails of the standard model(e.g large invariant masses, tails of distributions)

• the accurate and precise determination of the standard model physics iscrucial: (i) as a background to direct exotic searches (ii) as an indirectprobe of other physics



CDF’s list of “Very Exotic” searches

• Dilepton Resonances

– searching for Z ′, RS Extra Dimensions, Technicolor– using ee, µµ, ττ– results- YES

• Same-Sign Dilepton Resonances

– searching for H++

– using ee, µµ, eµ, ττ– results- YES

• Dilepton+Photon

– searching for heavy leptons



– using eeγ, µµγ, ττγ– results- YES

• Dilepton+Di-jet

– searching for leptoquarks– using eejj, µµjj, ττjj, eνjj, µνjj, τνjj, ν– results- YES

• Photon+missing ET

– searching for ADD Graviton– using γ + missing ET

– results- YES

• Photon+jet

– searching for b′

– using γ + missing ET



– results- in progress

• Highly-ionizing (slow) track

– searching for H++,H−−, monopoles, UEDs stops and staus– results YES



Di-leptons

pp → X → `+`− : Two energetic, isolated, same flavor, opposite sign leptons

– pp → `+`− Drell-Yan irreducible, calculable, simulable, estimated to 10%.– “fake” leptons, i.e. b → c`ν, conversions, K+ → µν. Not predicted. Estimated

from data control samples to ∼30-50%. Not significantly contributing at highmasses.

– cosmics in the muon channels always more of a problem than one might think.Estimated to ∼30-50%. Trouble.

– W+jets, di-bosons, top negligible at high mass



e.g. Di-electron, Di-Muon invariant mass at the Tevatron

the uncertainty on total background estimate for M`` > 300 is 40%for electrons, and 25%for

muons.

systematics come from luminosity, acceptance, energy/momentum scale/resolution, selection

efficiency, background statistics/normalization.



D0 di-electorn search for TeV−1 extra dimensions (KK bosons) → MC > 1.12 TeV. The

sensitivity at the Tevatron for 2fb−1 using dileptons and both experiments is 2.3 TeV and for

LHC(14TeV, 100 fb−1 1-3% systematics) 13.5-15.5 TeV. (95% C.L., Cheung SUSY 2004)

no BSM high mass same flavor dilepton pairs

• so-called “sequential” Z ′

• other Z ′ models (Z ′ψ,Z′χ,Z

′η,Z

′I )

• ZH from a little Higgs model

• technicolor particles ωT and ρT

• Randall-Sundrum gravitons

• large extra dimensions

• R-parity violating sneutrinos

e.g. acceptance as a function of spin

– 20 pb−1 Z ′ 505 GeV/c2

– 90 pb−1 Z ′ 640 GeV/c2

– 200 pb−1 Z ′ 750 (780) GeV/c2∗

* CDF (750) fits M``, D0 uses mass window cut and counting

e.g. Di-gamma

e.g. Di-electron, Di-Muon |cosθ| (Collins Sopper)

e.g. missing energy/monojet type of analyses

ATLAS’s list of “Very Exotic” searches

PDG 2004 on BSM Searches

this goes in the end for Savas’ new thingy

Magnetic Monopoles

“At the present time [1975] there is no experimental evidence for the existence ofmagnetic charges or monopoles, but chiefly because of an early, brilliant theoreticalargument by Dirac, the search for monopoles is renewed whenever a newenergy region is opened up in high energy physics or a new source ofmatter, such as rocks from the moon, becomes available.”

PDG 2004 on BSM Searches

Magnetic Monopoles

“At the present time [1975] there is no experimental evidence for the existence ofmagnetic charges or monopoles, but chiefly because of an early, brilliant theoreticalargument by Dirac, the search for monopoles is renewed whenever a newenergy region is opened up in high energy physics or a new source ofmatter, such as rocks from the moon, becomes available.”

J. D. Jackson, Classical Electrodynamics, 2nd edition (John Wiley Sons, NewYork, 1975).

Monopole Production Cross Section

X-SECT (cm2) MASS (GeV) ENERGY( TeV) BEAMS

KALBFLEISCH 04

< 0.6E-36 >265 1.8 pp

< 0.2E-36 >355 1.8 pp

< 0.07E-36 >410 1.8 pp

< 0.2E-36 >375 1.8 pp

KALBFLEISCH 00

< 0.7E-36 >295 1.8 pp

< 7.8E-36 >260 1.8 pp

< 2.3E-36 >325 1.8 pp

< 0.11E-36 >420 1.8 pp

KALBFLEISCH 04 reports searches for stopped magnetic monopoles in Be, Al, and Pb samples obtained from discarded material from the

upgrading of D0 and CDF. A large- aperture warm-bore cryogenic detector was used. Results are model dependent. KALBFLEISCH 00 used

an induction method to search for stopped monopoles in pieces of the D0 (FNAL) beryllium beam pipe and in extensions to the drift chamber

aluminum support cylinder. Results are model dependent.

Scale and Geometry

– From contact interaction to a gauge boson : the GFE2 behavior was tamed atshort length scales

– From gauge theory to string theory the GNE2 seems to get tamed at evenshorter length scales∗ implies a change in how we perceive spacetime geometry & dynamics → extra

dimensions∗ The Standard Model, Supersymmetry & Kaluza-Klein theory under one

umbrella

energy scale(s) of EDs

Bring down the Planck → GUT → TeV scale

in string theory with extra dimensions making the 5th slightly bigger (compared to the Planck

length), and then even bigger and then more of them large:

Kaluza-Klein → Witten-Horava → Lykken → ADD, RS...

energy scale(s) of EDs

What is it?

– GUT/Planck/string/see− saw scale 1015 − 1019 GeV ?– TeV 102 − 104 GeV– dark energy scale (TeV 2/MPlanck)

What can it be?

Solution to all problems

picture credit JoAnne Hewett

– EWKSB, flavor breaking, SUSY breaking, hierachy problem & tc– ... EDs have not (yet) been invoked to solve High Tc superconductivity...



The Scenariiscenario=set of physics assumptions that with work could turn into a respectable model

– Large compact extra dimensions (ADD)Warped extra dimensions (RS)inverse TeV extra dimensions (Antoniadis)(most) all hybrids and combinations of above (Davoudiasl, Carena ...)

– Fat branes, skiny branes, solid branes, soft branes, no branes, quivering branes,positive branes, negative branes, curved bulk, flat bulk, supersymmetric bulk,gravity in the bulk, gauge fields in the bulk, no gauge fields in the bulk, fermionsin the bulk, no fermions in the bulk, right handed neutrinos in the bulk, &tc



The questions

How many dimensions at each scale? What is the compactification? thegeometry of the bulk? What are the background fields? What symmetriesbreak and what not? Are there stabilizing fields? What is gravity doing? Whois on the brane and who is on the bulk? Who has KK modes? Who getsvolume-supressed coupling?



brief (common) model description



brief common model description



Collider Signatures

– KK-Graviton Emission., KK-Graviton Exchange, KK-Graviton ResonantProduction, KK-Boson Resonant production ...

– Monojets+Missing Energy, Dijets+Missing Energy, Monophotons+MissingEnergy, Diphotons+Missing Energy, Dijets, Dileptons, Dileptons+missing energy,Diphotons, Dibosons ...

– Results/Studies LEP, TeVI, TeVII, LHC, NLC/TESLA



is it ED or is it not?

– not obvious experimentally accessible smoking guns

– many multi-channel analysis to confirm discovery



experimentally speaking

Work to figure out

– how to distinguish EDs from other stuff

– what are the experimental handles on the different ED scenarii

– what are the channels of direct/indirect ED observation and how they areconnected

– how to establish benchmark models and event generation

– how to use collider/flavor/astro signatures and constraints(there is a lot of creative confusion here)



Results on RS models



Plethora of final states



G → Z0Z0



G → WW → `ν+jets



easiest cases: RS models

1500 GeV KK graviton/its tower of states at the LHC

Allanach et al. hep-ph/0211205

Davoudiasl et al. hep-ph/9909255



but not too easy!

– (a) gg → G→ ff

– (b) qq → G→ ff

– (c) gg → G→ gg, γγ

– (a) qq → G→ gg, γγ

– (d) gg → G→ WW,ZZ

– (e) qq → G→ WW,ZZ

– (f) gg → G→ HH

– (g) qq → G→ HH



ADD models

– example graviton emission → spectacular monojet+missing energy signature



smooth excess over Standard Model: ADD models

– On shell production of KK gravitons produces smooth missing energy distribution after

convolution of closely spaced KK spectrum with PDFs

my prl picture Ian’s picture



brane models with flat TeV−1 size EDs

– SM gauge bosons live in the bulk

– KK gluon exchange enhances di-jet cross section at high pT

Lykken et al. PL B485, 224 (2000)

Dicus et al. hep-ph/0012259



dijet cross section LHC

– excess at high pT

– sensitivity up to 15 TeV!

– (but can you tell if it is ED or other stuff?)



dijet invariant mass bumbs?



The Detectors



universal extra dimensions

– one compactified extra dimension

– everybody lives in the bulk

Appelquist et al. hep-ph/0012100

Matchev et al. hep-ph/0205314



SUSY’s clone spectrum

UED spectrum from matchev’s paper



UED-SUSY separation

– if kinematically accesible look for heavier KK modes

– “KK-onia” Carone et al. hep-ph/0312055

– heavy flavor Buras et al. hep-ph/0307202 &tc

– ...



Hybrid cases

e.g One flat compact ED and one RS type ED (Davoudiasl, Hewett, Rizzo)

Interesting mapping of the extra space geometry



Remarks I

– The scenarii mentioned constitute a radical departure from the SM

– There are ED scenarii that assume modified SUSY desert

(Kawamura et al. hep-ph/0012125, Altarelli et al. 0102301

Hall and Nomura hep-ph103125 ...)

– There is a plethora of scenarii and the number will only increase

– Until (soon) we get some experimental guidance about EWSM, Higgs, SUSY



Remarks II

Extra dimensions are

– not only a model-building tool

– not only a program for theory job positions

– not only summoning mere mortals to Paris

The discovery of extra dimensions

– will beat the superlative of any human achievent

– needs a strong and long experimental program



Remarks III

– Anything new at high energies will clue us in

– The models are models not theories –

but when you find even one solution to a tough problem you take it seriously and investigate it

exhaustingly with experimental tests

– We do this kind of physics scale by scale and we are lucky to be breaking into crucial energy

scales experimentally today



Overview


status of beyond the sm searches - university of...

Documents