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Conference Date: 
Lundi, Juin 2, 2008 (All day) to Vendredi, Juin 6, 2008 (All day)
Scientific Areas: 
Particle Physics
Quantum Fields and Strings


PASCOS 08 is the 14th in a series of interdisciplinary symposia on the interface of particle physics, string theory and cosmology. Since the first PASCOS symposium in 1991 the interaction between these disciplines has only increased and with an accelerating pace.


With the startup of LHC and the launch date of the Planck satellite both at hand, as well as many other exciting experiments under way or being planned, PASCOS-08 will look into an exciting future. It will give theorists an opportunity to prepare for this wealth of new data and the stringent tests to which they will subject the existing theories.


The aims of the conference are to review the recent progress in particle physics, string theory and cosmology, promote the exchange of ideas and discuss the future. While the conference is mainly aimed at theorists, there will also be a strong experimental component, with discussion of new results and future experiments.



Alexis Aguilar-Arevalo, TRIUMF

Results from the MiniBooNE Experiment

We present the results from the MiniBooNE neutrino oscillations search in which no significant excess of events is observed above background in the energy range from 475 MeV to 3000 MeV. For lower energies an excess of events that is not consistent with a two neutrino oscillation model is observed. We present recent advances in the understanding of this excess, including a study of muon and electron neutrinos from the nearby NuMI neutrino source. The techniques used in the first oscillation analysis are discussed as well as tose of a recent analysis that combines two different electron neutrino candidate samples with a high statistics muon neutrino sample in the oscillations fit to reduce systematic uncertainties.


Nima Arkani-Hamed, IAS (Princeton)

Gianfranco Bertone, IAP

Particle Dark Matter: What Comes Next?

After a brief introduction, where I review the properties of the "good Dark Matter candidate" and the status of accelerator, direct and indirect Dark Matter searches, I will show that a conclusive identification of DM particles can most likely be achieved only through a "multidisciplinary" approach, that combines together different detection techniques. I will place special emphasis on the upcoming Large Hadron Collider, and on the gamma-ray satellite GLAST (scheduled for launch on June 3, i.e. the day after the talk...).

Francois Bouchet, AIP


Alessandra Buonanno, University of Maryland

Probing fundamental physics and the early Universe by detecting gravitational waves

I will discuss how the direct detection of gravitational waves can be used to disclose the dark age of the Universe, and to probe fundamental physics and cosmology. I will compare theoretical predictions with current and upcoming experiments.


Alex Conley, University of Toronto 

Three years of cosmology with SNLS

The Supernova Legacy Survey is the largest current high-redshift supernova survey, with the goal of measuring the mean equation of state of dark energy to better than 10%.  I will discuss the 3rd year SNLS cosmological analysis and the ways in which our data can be used to test and refine the utility of supernovae as cosmological probes.


Joanna Dunkley, Oxford University 

Cosmology from WMAP 

Victor Flambaum 

Variation of Fundamental Constants From Big Bang to Atomic Clocks: Theory and Observations

Theories unifying gravity with other interactions suggest temporal and spatial variation of the fundamental "constants" in expanding Universe. The spatial variation can explain  fine tuning of the fundamental constants which allows humans (and any life) to appear. We appeared in the area of the Universe where the values of the fundamental constants are consistent with our existence. I present a review of  works devoted to the variation of the fine structure constant alpha, strong interaction and fundamental masses (Higgs vacuum). There are some hints for the variation in  quasar absorption spectra and  Big Bang nucleosynthesis data.  A very promising method to search for the variation consists in comparison of different atomic clocks. Huge enhancement of the variation effects happens in transitions between very close  atomic, nuclear and molecular  energy levels. Large enhancement also happens in nuclear, atomic and molecular collisions near resonances. How changing physical constants  may occur? Light scalar fields very naturally appear in modern cosmological models, affecting parameters of the Standard Model  (e.g. alpha). Cosmological variations of these scalar fields should occur because of drastic changes of matter composition in Universe: the latest such event is rather recent (about 5 billion years ago), from matter to dark energy domination. Massive bodies  can also affect physical constants. The strongest limits  are obtained from the measurements of dependence of atomic frequencies on the distance from  Sun (the distance varies due  to the ellipticity of the Earth's orbit).

 Ben Grinstein, UC San Diego

Unitary Representations of the Conformal Group for pedestrians


We comment on several points concerning unparticles which have been overlooked in the literature. One regards Mack's unitarity constraint lower bounds on CFT operator dimensions,e.g,. d>= 3 for primary, gauge invariant, vector unparticle operators. We correct the results in the literature to account for this, and also for a needed correction in the form of the propagator for vector and tensor unparticles. We show that the unitarity constraints can be directly related to unitarity requirements on scattering amplitudes of particles, e.g., those of the standard model, coupled to the CFT operators. We also stress the existence of explicit standard model contact terms, which are generically induced by the coupling to the CFT (or any other hidden sector), and are subject to LEP bounds. Barring an unknown mechanism to tune away these contact interactions, they can swamp interference effects generated by the CFT. 

Concha Gonzalez-Garcia, SUNY Stony Brook & Barcelona University

Phenomenology of Massive Neutrinos


Diego Hofman, Princeton University 

Conformal Collider Physics

Andrew Lange, Caltech

The Fragility of Higgs Boson Predictions for the LHC

Avi Loeb, Harvard University

Fundamental Physics from 21cm Cosmology

The atomic hydrogen gas left over from the Big Bang was affected by processes ranging from quantum fluctuations during the early epoch of inflation to irradiation by the first galaxies at late times. Mapping this gas through its resonant 21cm line serves a dual role as a powerful probe of both fundamental physics and astrophysics. Current cosmological data sets (such as galaxy surveys or the microwave

background) cover only 0.1% of the comoving volume of the observable Universe. 21cm observations hold the potential of mapping matter through most of the remaining volume. Radio observatories are currently being designed and constructed with this goal in mind. The three-dimensional 21cm maps could potentially set unprecedented statistical constraints on the power spectrum of cosmic density fluctuations and its gravitational growth with cosmic time. The reduced uncertainties could allow for precise measurements of fundamental parameters, such as the mass of the neutrino or the equation of state of the dark energy (from acoustic oscillations in the 21cm power spectrum), and will test generic predictions of cosmic inflation for deviations of the density fluctuations from scale invariance and gaussianity. The measured gravitational growth of the fluctuations with cosmic time would constrain the nature of the dark matter or alternative theories of gravity.

Paul Mackenzie, Fermilab

Lattice Gauge Theory in the LHC Era

Lattice QCD in this decade has succeeded in producing essential results for crucial components of Standard Model phenomenology such as constraints on the rho-eta plane.  Much more will be required of lattice gauge theory in the LHC era:  sub-per cent precision in QCD quantities and the ability to calculate in strongly interacting sectors of Beyond-the-Standard-Model theories such as SUSY or technicolor.  I will review the status of current calculations and the prospects for accomplishing what needs to be done in the coming years

Art McDonald, Queen's University 

SNO and the New SNOLAB Underground Facility

The Sudbury Neutrino Observatory (SNO) has now completed neutrino detection with 1,000 tonnes of heavy water situated 2,000 meters underground in Vale-INCO’s Creighton Mine near Sudbury. The final phase of operation involved an array of neutron detectors to observe the neutral current reaction of solar neutrinos on deuterium. These measurements define the flux of all neutrino types from the Sun with very different systematic uncertainties than previous phases of SNO. Comparing this measured flux with the flux of electron neutrinos observed with the charged current reaction on deuterium clearly exhibits neutrino flavor change and accurately determines neutrino properties. The underground facility is now being expanded to create a long-term international facility for underground science (SNOLAB), where measurements of Dark Matter, Double Beta Decay, Solar and Supernova Neutrinos will be performed with the lowest radioactive background available anywhere. First results from the final operational phase of SNO, the future plans for the SNO detector and the plans for other experiments at SNOLAB when it is completed in 2008 will be described.

Rob McPherson, University of Victoria & TRIUMF

LHC: The Countdown

The CERN Large Hadron Collider is nearing completion.  Both the ATLAS and CMS experiments are being completed, and the accelerator is proceeding through cool-down to cryogenic temperatures in preparation for first beam.  The timescales and prospects for first beam, collisions and physics will be discussed, and the early physics program of the LHC high PT experiments reviewed.


Hans Peter Nilles, Bonn University 

From Strings to the MSSM


Uwe Oberlack, RICE University 

Direct Dark Matter Searches

Astrophysical evidence indicates that the universe consists to about 25% of non-baryonic, cold Dark Matter, compared to merely ~4% of "regular" matter, composed of quarks and electrons. The existence of Dark Matter and Dark Energy is striking evidence for physics beyond the Standard Model, and understanding their nature ranks among the foremost questions in science today. If the bulk of matter in the universe consists of relic massive particles moving at non-relativistic speeds, we may be able to detect these particles in direct searches with low background experiments. This talk will focus on the search for weakly interacting massive particles (WIMPs), predicted in particular by theories invoking supersymmetry. The recoils of target nuclei resulting from elastically scattering WIMPs should be detectable in principle with sensitive detectors. I will review the current status of direct Dark Matter searches, and then elaborate on the XENON suite of experiments. The XENON Dark Matter program was established in 2002, and reached a major milestone with the installation of its first Dark Matter detector, XENON10, at the Gran Sasso underground laboratory in Italy. XENON10 reported the world-best limits on spin-independent WIMP-nucleon cross-sections last year. (CDMS-II has recently improved their limits even further.) Meanwhile, we are building the next generation detector XENON100 at the same location. The new detector will feature ten-fold greater fiducial mass and 100 times improved background. We anticipate first results by the end of the year. I will report on the status of XENON100 and its projected sensitivity, and conclude with an outlook on the prospects of the field.

Keith Olive, University of Minnesota

Big Bang Nucleosynthesis: Concordance of Theory and Observations

An overview of the standard model of big bang nucleosynthesis (BBN) in the post-WMAP era is presented.  With the value of the baryon-to-photon ratio determine to relatively high precision by WMAP, standard BBN no longer has any free parameters.

In this context, the theoretical prediction for the abundances of D, He3, He4, Li6, and Li7 is discussed. The observational determination of the light nuclides is also discussed.

Emphasis is placed on systematic uncertainties in He4 observations and the present Li7 discrepancy. Possible explanations for the latter are reviewed.

James Peebles, Princeton University

State of the Cosmological Tests

I will argue that the network of cosmological tests has grown broad and tight enough to show that the current standard LCDM cosmology, dark matter, dark energy and all, is a good approximation to reality. That doesn't mean it is reality: we make progress by successive 

approximation. And in the application of this cosmology to issues of galaxy formation there are challenges that could be telling us that we need a better cosmology, or perhaps only that galaxy formation is complicated. Either way, we can conclude that when LCDM is replaced by something better the new cosmology will predict a universe that looks very much like LCDM.

Tilman Plehn, University of Edinburgh

TeV-Scale Physics in the LHC Era

Fernando Quevedo, Cambridge University

Cosmological Implications of LARGE volume string compactifications

Recent progress on the cosmological implications of the large volume string scenario is reviewed. 

Krishna Rajagopal, MIT

Quark Gluon Plasma in QCD, at RHIC, and in String Theory

Nathan Seiberg, IAS (Princeton) 

Gauge mediation of SUSY breaking

Eva Silverstein, Stanford University

Monodromy in the CMB:  Gravity Waves and String Inflation

The sensitivity of inflationary models to Planck-suppressed operators motivates modeling inflation in string theory.  The case of high-scale inflation is particularly interesting both theoretically and observationally.

Observationally it yields a gravity wave (B mode polarization) signature, and theoretically it requires a large field excursion which is particularly sensitive to UV physics.  I'll present a simple mechanism derived recently in collaboration with A. Westphal for obtaining large-field inflation, and hence a gravitational wave signature, from string theory.  The simplest version of this mechanism, arising on twisted torus compactifications of string theory, yields an observationally distinctive version of chaotic inflation with a potential proportional to the 2/3 power of the inflaton, falsifiable on the basis of upcoming CMB measurements.  This mechanism for extending the field range arises widely in string compactifications, though in all cases it requires sufficient symmetry to control the corrections to the slow-roll parameters.

I will finish by describing further developments in this direction.

Paul Steinhardt, Princeton University

Some Thoughts on Dark Energy, Inflation and Extra Dimensions

This talk will present some theorems relating dark energy (and inflation) and fundamental theories obtained by compactifying extra dimensions.

Leonard Susskind, Stanford University 

Negative Curvature


I will discuss the possibilities for a post-standard-cosmological-model phenomenology based on the assumption that our universe was born in a tunneling event from an earlier "Ancestor" vacuum.

J. Anthony Tyson, UC Davis

Multiple probes of Dark Energy

The Large Synoptic Survey Telescope will survey 20,000 square degrees in six bands from 320 to 1050 nm imaging each region 1000 times in ten years of operation. The 27.5 magnitude limit enables photometry of ten billion galaxies to low surface brightness and shape measurement of several billion galaxies.  A number of independent cross-checking probes of the nature of dark energy will result.  Using many photometric redshift bins, the joint analysis of 2-D baryon acoustic oscillations and weak lensing is particularly powerful.  These and other unique probes of dark energy involving the deep wide-area time domain data will be described.  The LSST probes of dark energy are complementary to proposed space missions.

Brigitte Vachon, McGill University

Physics at the Tevatron

The Fermilab Tevatron is currently the highest energy particle collider in the world and is host of the CDF and DZero experiments. Measurements performed by these two international collaborations have significantly improved our knowledge of subatomic physics and helped further constrain different scenarios of physics beyond the Standard Model. A summary of some of the latest results and future experimental goals of the Tevatron's experiments will be presented.

Cumrun Vafa, Harvard University

F-theory and GUTs: Experimental Predictions

Alexander Vilenkin 

Measures of the Multiverse

Inflation is generically a never ending process, with new "pocket universes" constantly being formed.  All possible events will happen an infinite number of times in such an eternally inflating universe.  Unless we learn how to compare these infinities, we will not be able to make any predictions at all.  I will discuss some proposed approaches to this "measure problem".


James Wells

The Fragility of Higgs Boson Predictions for the LHC

The Higgs boson is the only scalar particle in the Standard Model. Precision electroweak analyses suggest that it should be light -- less than 200 GeV.   These facts combined with the speculative nature of all electroweak symmetry breaking discussions imply significant uncertainty in discovering a Higgs boson. I discuss the unique aspects of a Higgs sector, highlight the New Physics origins of uncertainty for its phenomenology, and suggest a broader framework with which to approach Higgs boson phenomenology at the LHC.

Tsutomu Yanagida, Tokyo University 

Conformal SUSY Breaking and Cosmological Constant

Bill Zajc, Columbia University 

Quark Gluon Plasma at RHIC (and in QCD and String Theory)

Funding provided in part by:

Perimeter Institute

Canadian Institute for Advanced Research

University of Waterloo


The Institute of Particle Physics


Origins Institute