Workshop on the interconnection between particle physics and cosmology Gordy Kane Texas A&M May 2007

SUMMARY FROM PARTICLE PHYSICS VIEW IT’S ALL PARTICLE PHYSICS! INTERNATIONAL WORKSHOP ON THE INTERCONNECTION BETWEEN PARTICLE PHYSICS AND COSMOLOGY

Interesting and significant cultural differences between cosmologists, astronomers, particle physicists, between experimenters and theorists Summarize? Little new data Little qualitatively new theory Future easy to predict Lots of good ideas and goals Should get as much physics as possible from existing and almost existing facilities Cosmology summary – it’s all cosmology

 Cosmology and astrophysics  the universe is composed of matter but not antimatter, but they cannot tell us why.  Cosmology and astrophysics  a quarter of the universe is dark matter, but they cannot tell us what the dark matter is.  Cosmology and astrophysics  the universe began with three space dimensions growing rapidly, but they cannot tell us what physical effect caused that inflation, what the inflaton was.

IF NATURE IS SUPERSYMMETRIC, WE CAN ADDRESS THESE QUESTIONS, AND LHC DATA CAN PROVIDE ESSENTIAL CLUES FOR ALL THESE QUESTIONS

Cultural question – what are the most important problems to focus on?

Dark matter – but what is the dark matter? -- three candidates suggested by data and good theories, neutrinos, axions and lightest superpartner (LSP) – presumably all present, perhaps others -- question is how much of each – must detect signal of each, then must calculate relic density of each -- (Ω ν <0.01 from WMAP etc) – LSP relic density calculations require knowledge of cosmology, superpartners masses and couplings, LSP combination of bino, wino, higgsinos – Tevatron relevant, maybe crucial COSMOLOGY CONSTRAINS DARK MATTER PROPERTIES, BUT NEED PARTICLE PHYSICS TO SUPPLY THE DARK MATTER PARTICLE – KNOWLEDGE OF LSP CRUCIAL Dark Matter Inverse Problem

What is the inflaton? Cosmology and astrophysics  the universe began with three space dimensions growing rapidly, but they cannot tell us what physical effect caused that inflation, what the inflaton was. -- RH sneutrino? -- A superpartner… -- flat directions in squark-slepton space (Dutta et al) -- scalar fields from string theory (moduli), e.g. recent approaches have moduli potentials from “fluxes” (generalizations of electromagnetic fields) -- also have supersymmetry broken by fluxes  superpartner masses and interactions, measured at colliders, can determine inflation parameters -- quantum fluctuations All contribute – which dominates if any? Most are related to other observable particle physics COSMOLOGY CONSTRAINS INFLATON “POTENTIAL” BUT NEED PARTICLE PHYSICS TO SUPPLY THE INFLATON Inflaton Inverse Problem

Origin of matter asymmetry? -- cosmology tells us universe began from neutral vacuum and initially was equally matter and antimatter – and now mainly matter, not antimatter – but cannot tell us why -- actually several good ways to get matter asymmetry – leptogenesis, EW baryogenesis, Affleck-Dine, fluxes, hidden sector – need particle physics to generate the asymmetry -- main methods use supersymmetry, or need it to have a high scale consistently in the theory All may contribute – calculate how much from each Matter asymmetry Inverse Problem

DARK ENERGY What is it? w= -1 ± 0.05 – 0.1 ~2 problems for understanding -- why no large quantum fluctuations? -- calculate the size of the actual DE  why now, coincidence issue Don’t know what DE is – but not “nobody has any idea” – rather, being studied by many people with a number of ideas Modify gravity Scalar fields “quintessance” Quantum fluctuations calculated less naively Some approaches do relate DE semi-directly to other physics, some do not – related by underlying theory What data would help? -- any deviation from w=-1, at earlier times

LHC INVERSE PROBLEM(s) Is there a signal beyond the SM? Experimenters plus SM theorists will get this right – relevant work underway Is it supersymmetry? -- Can we learn what superpartners are produced at the LHC? -- Can we distinguish susy from …at the LHC? -- Can we distinguish susy from something we haven’t even thought of at the LHC? -- Can we measure superpartner spins at the LHC? Can we learn enough about the LSP (combining LHC info with experiments that detect it in the laboratory or in space) to compute the relic density of the LSP and see how much of the dark matter it is? Can we learn enough about the underlying theory so we can measure some parameters and use the theory to determine the rest of what we need to compute the LSP relic density, and the relic density of any other candidates?

Why do we particularly need LHC to understand nature more deeply?

I think I live in a string theory ground state, vacuum - - What form might physics take in the best of all possible string vacua? In a supersymmetric world we can test string theory predictions at the LHC, and study the implications of LHC data for string theory An optimist can make a defendable argument that LHC data could lead to testing and establishing string theory and to learning many “why’s” – once we have a theory with many experimental tests it covers other areas

Wimp detectors Several working or about to! Direct XYPQ-mn, positron excess, antiproton excess, GLAST, neutrinos – PAMELA, AMS? Remarkable achievements! Ideas and R&D for even better ones! U.S. funding level very embarrassing – community should scream Wimp hints Diffuse gammas – de Boer Positron excess -- Olzem

e + /(e + +e - ) Jan Olzem, arXiv: , Combined data from HEAT, AMS, other sources

NOTE  Perhaps CMB (maybe with weak lensing) will get to ∑m  0.15 eV and see signal (  neutrino masses about degenerate), or see no signal (  neutrino masses hierarchical) – Dunkley (Huterer)  Otherwise neutrinos behaving as naively expected  Axions – probably present in any string theory -- experiments making good progress

TEVATRON COLLIDER Should get 6-8 fb -1 before unwisely closed -- Then could be sensitive to Higgs boson if detectors and resolutions and experimenters all work well Probing some new physics windows such as B s  μ + μ - -- SM prediction ~ 3x10 -9 – experiment will get limit a few times that if no discovery Chance for supersymmetry signals, e.g. same sign dileptons, a very generic signal since it originates with Majorana fermions

Discovery/Luminosity Roadmap? 100 fb -1 /yr SHUTDOWN 1000 fb -1 /yr 200 fb -1 /yr fb -1 /yr First physics run: O(1fb -1 ) F. Moortgat, A. De Roeck Next 10 years would be a very exciting period in the history of Particle Physics (and Cosmology). From Tomio Kobayashi First rumors by End of 2008

Exciting new possibilities in accelerator physics Peter McIntyre upgrades Muon collider in Fermilab tunnel? [upgrade in the SSC tunnel?]

REMEMBER Goal today of particle physics (and its subfield cosmology) -- not only description of world, but understand why it is that way Probably have learned in recent decades that getting “why” understanding implies going beyond 4D -- supersymmetry has fermionic dimension for each space-time one -- string theory extra dimensions allow addressing more (all?) why questions NEED DATA TO GUIDE US IN THE EXTRA DIMENSIONS LHC (and ILC) and DM (and DE) data could provide the experimental base to go far toward deeper understanding OPTIMISM ABOUT DISCOVERIES AND ABOUT UNDERSTANDING JUSTIFIED