Cosmology at the Microscopic Scale

CMS

Compact Muon Solenoid

B. Paul Padley, Rice University

B. Paul Padley

What a Great Time to Be a Physicist

There is certainly an abundance of ideas

B. Paul Padley

What a Great Time to Be an Experimentalist

• The theorists have been generating lots of fascinating ideas

• Unfortunately they have not been well constrained by experiment

• Now the experiments are about to be turned on

• We are going to find some answers

• What are the odds most (all?) of the theorists are wrong?

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CMS

• So lets use a Compact Muon Solenoid (CMS) to look for detector for things of cosmological interest,

• or at least of interest to some cosmologists.

B. Paul Padley

B. Paul Padley

B. Paul Padley

The Reason for the Interest

gg luminosity @ LHCqq luminosity @ LHCgg luminosity @ Tevatronqq luminosity @ Tevatron

The LHC is a Discovery Machine

The first accelerator to probe deep into the Multi-TeV scale

Many reasons to expect new TeV-scale physics

Parton-Parton CM Energy

1000 2000 3000 4000 5000 6000

LHC

Tevatro

n

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Compact is a Relative

Term

CMS is significantly smaller than ATLAS

but heavier

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B. Paul Padley1920 Tonne piece of detector, with superconducting magnet being lowered down.

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Cosmic Ray Data

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Status

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How much data when?

• LHC will turn on in late spring 2008 and expects to get to by the end of two years

• Expect < 5fb-1 in the first year

• Will subsequently be increased to 1034

• This is a tremendous luminosity, cf. next slide

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Example Production Rates

At this luminosity collect 20fb-1 per year

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Stored Energy

• The stored energy in one LHC beam is ~360MJ at 1034

• That is enough energy to melt 0.5Ton of copper!

• Must turn the beam on with care

• More importantly: Dump that beam with care!

B. Paul Padley

Caveat Emptor

• So I have done none of the analyses presented here.

• I have been busy with getting CMS up and running

• Fortunately I have a bright post-doc, Alex Tumanov, who helped me with this talk

• As a side note, along with hosting conferences like this, the Texas A&M is making important contributions to the CMS detector. – They are an impressive group and fantastic things are

happening in their department here

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A word on the SM Higgs

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SUSY

Just like ATLAS, there is a lot of effort being expended analyzing various SUSY scenarios.

All the results I will present, and lots that I wont, are available in our physics TDR

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Missing Et ?

Have MET as a “diagnostic trigger”? V. Buscher – Run II at CDF and D0 shows that with all the preparation it still will be hard. Try to use top pairs as a benchmark. Top samples will have jets, leptons and MET. Need to establish MET before searching for SUSY.

D0

CDF

Slide from Dan Green

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Extra Dimensions

From Monograph by Terning: http://particle.physics.ucdavis.edu/modernsusy/index.html

The purple peaks show the gauge coupling of the Seiberg-Witten theory as a function of the moduli space; the associated tori are shown in yellow. The quantum deformed moduli space of SUSY QCD is shown in turquoise. A slice of anti-de Sitter space is shown in orange.

B. Paul Padley

Kaluza-Klein

• You will often hear reference to Kaluza-Klein excitations, and that is certainly something we will look for at the LHC.

• So I thought I will give my simple minded experimentalists explanation of what these are.

B. Paul Padley

Undergraduate Quantum

• Remember your undergraduate quantum mechanics.

• If a free particle is traveling through the vacuum, you can describe it with a wave packet.

http://www.cs.unm.edu/~dstrain/sem/results.html

B. Paul Padley

Undergraduate Quantum

• If a particle is trapped in a box you describe it as a summation of normal modes of the box

http://www.physchem.ox.ac.uk/~hill/tutorials/qm1_tutorial/pib/index.html

B. Paul Padley

Undergraduate Quantum

• In a Benzene ring you can calculated the energy levels for an electron going around the ring.

• Again you get normal modes

• These correspond to matching the phase and amplitude at the =0, =2 boundary– m quantum number in the

hydrogen atom is the same thing.

B. Paul Padley

Compact Extra Dimensions

• When you have a particle traveling in compact extra dimensions as well as our space you get a mixture of these two things.

• In our space there is a wave packet• In the compact space there are normal

modes• These must be combined to get the

complete description of the particle

B. Paul Padley

Normal Modes = Mass Bumps

• In our space we see the normal modes of the other dimensions as excited states.

• That is: If a particle is traveling in both the extra dimensions and our space then we will see a tower of mass excitations corresponding to the normal modes in the compacted extra dimensions.

Drell-Yan at the LHC

1.5TeV/c2 Graviton for various values of k/Mpl in Drell-Yan production

Davoudiasl, Hewett, Rizzo PRD 63, 075004 (2001)

B. Paul Padley

Drell-Yan

• This is fantastic:– The first thing we will

study at the LHC is the Drell-Yan processes.

– These are a way we calibrate the detector (we look for the Z0, our calibration signal)

Not just muons, any lepton pairs can come out

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Dilepton

• At CMS we looked at possibility of observing resonance peaks (“bumps”) that are predicted by various models

• These usually are KK excitations of a Graviton and Z boson in several models such as Randall-Sundrum, other ED, etc

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Simulated Event

Simulated Z’ event decaying to two muons.

This is the easiest thing you can do at the LHC!

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Example KK Z

Example of a 4TeV/c2 Kaluza-Klein Z with 30fb-1

Grey area is the SM Drell-Yan spectrum

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Discovery Potential

5 KK Z discovery potential as a function of Mass and integrated luminosity

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Example Graviton

Example of a 1.5TeV/c2 Kaluza-Klein graviton with 30fb-1

c=k/M=0.01

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Dielectron Discovery Potential

Randall-Sundrum type gravitons

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Dimuon “bumps”

Reach of the CMS experiment as a function of the coupling parameter and the graviton mass for various values of integrated luminosity; the left part of each curve is where significance exceeds 5σ

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Diphoton

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ADD

Arkani-Hamed, Dimopoulos, Dvali

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Large Extra Dimensions

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Dimuon spectrum enhancement

• ADD model is expected to be observed via non-resonant modifications to the di-muon spectrum

• Plots at right show this for nextra=6 to 1 (bottom to top)

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Dimuon spectrum enhancement

• Plot to the right is significance as a function of physics scale: – Even for L=1fb-1

ADD contributions to Drell-Yan process show for M<4TeV

B. Paul Padley

Dimuon spectrum enhancement

• Plot to the right is significance as a function of physics scale: – Even for L=1fb-1

ADD contributions to Drell-Yan process observable for M<4TeV

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• MET for 30fb-1 in ADD model with n=2

Photon and Missing Et

• ADD type of ED models predicted to have such signals

Single VB at hadron or e+e- colliders

GKK

GKK

GKK

GKK

V

VV V

Diagrams from Landsberg

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Black Holes

Water sculpture by William Pye called Charybdis

B. Paul Padley

CHARYBDISCharybdis (kuh-RIB-dis). Mythological whirlpool off the coast of Sicily that sucked down vast quantities of water three times a day. Together with the monster Scylla, Charybdis was one of twin perils faced by Odysseus. The hero had been warned by Circe that the whirlpool could only be avoided at the cost of passing beneath the cliff harboring Scylla's lair. Sure enough, he timed his passage and steered clear of Charybdis only to lose six sailors to the many-headed Scylla.

Also a black hole generator http://www.ippp.dur.ac.uk/montecarlo/leshouches/generators/charybdis/manual.html

Χάρυβδις

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Perils of Odysseus

• We are on this Odyssey and it is going to be exciting

• Fortunately we wont be sucked into a black hole.– Although the 2.6 GigaJoules of stored energy

in the CMS magnet is not without its dangers.

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Black holes Radiate?

Graphic from: http://casa.colorado.edu/~ajsh/hawk.html

The prediction that black holes radiate due to quantum effects is often considered one of the most secure in quantum field theory in curved space-time. Yet this prediction rests on two dubious assumptions: that ordinary physics may be applied to vacuum fluctuations at energy scales increasing exponentially without bound; and that quantum-gravitational effects may be neglected. - Adam HelferJournal reference: Rept.Prog.Phys. 66 (2003) 943-1008Cite as: arXiv:gr-qc/0304042v1

B. Paul Padley

Well that wouldn’t be fun

• OK, so I am experimentalist totally unqualified to comment one way or the other

• So lets try to make some black holes and see if indeed they do radiate.

B. Paul Padley

Black Hole Production

• Main idea: when the c.o.m. energy reaches the fundamental Planck scale, a BH is formed; cross section is given by the black disk approximation:

RS

parton

parton

M2 = s

~ RS ~ 1 TeV ~ 10 m ~ 100 pb

Text and graphic from Greg Landsberg, Brown U

B. Paul Padley

LHC: Black Hole Factory

Drell-Yan +X

[Dimopoulos, GL, PRL 87, 161602 (2001)]

Spectrum of BH produced at the LHC with subsequent decay into final states tagged with an electron or a photon

n=2

n=7

Slide from Greg Landsberg, Brown U

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Making Black Holes: MBH > M*(Gravity)

Making Black Holes: MBH > M*(Gravity)

Multi-Leptons, Jets, (Higgs) and Missing ET

Multi-Leptons, Jets, (Higgs) and Missing ET

Hewett, Lillie, Rizzo, PRL 95, 261603 (2005)

Hewett, Lillie, Rizzo, PRL 95, 261603 (2005)

Evaporate “Democratically”in ~10-27 seconds

Evaporate “Democratically”in ~10-27 seconds

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Example Case

Effective Planck Mass 2TeV/c2

Black Hole masses between 4 and 14 TeV/c2

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Sphericity

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Discovery Potential

The signature for a spray of particles from Hawking radiation is quite distinct and the production cross section is large.

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Conclusions

• Details of the models I we looked at is not important

• The models consistently give interesting phenomenologies

• With the earliest data from LHC we will quickly be in a position to verify or refute a large number of theoretical ideas based on extra dimensons.

Backup Slides

B. Paul Padley

Sphericity

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Black Hole Production• Schwarzschild radius is given by Argyres et

al., hep-th/9808138 [after Myers/Perry, Ann. Phys. 172 (1986) 304]; it leads to:

• Hadron colliders: use parton luminosity w/ MRSD-’ PDF (valid up to the VLHC energies)

1

2

222

22

38

1

n

P

BH

PSBH n

n

M

M

MRMs )ˆ(

a

BHbaa

bas

M a

aBH

BH

MsBHBH

sx

Mfxf

x

dx

s

M

dM

dL

BHabdM

dL

dM

XBHppd

BH

BH

21

2

2

2

,

ˆˆ

tot = 0.5 nb (MP = 2 TeV, n=7)

LHCn=4

tot = 120 fb (MP = 6 TeV, n=3)

[Dimopoulos, GL, PRL 87, 161602 (2001)]

Slide from Greg Landsberg, Brown U

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ADD

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RS