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Explore the intersection of high-energy physics and cosmology in this talk. Learn about the history of HEP, the Standard Model, and current research on form factors. Discover the connections between physics and astronomy, and the plans for using the LBT for a lensing survey.
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From the Littlest to the Largest: QCD to the LBT The intersection of HEP and Cosmology M.S.S. Gill OSU Astronomy Department Colloquium Thursday, November 30, 2006
Talk Plan • A short history of HEP (high energy physics) • The Standard Model edifice • My work on form factors (i.e. the B meson internal wavefunction) and relation to QCD • A very significant era coming up for HEP • Analogies and connections with cosmology • Where weak lensing fits in • Our plans for using the LBT for a lensing survey
The things to take away • After evolving separately for decades, physics and astronomy have strongly rejoined as one field – overlap in DM especially.. • Essentially how the Universe came to be, and what it’s made, of are inextricably linked ideas at root. http://watershed.ucdavis.edu/skeena_river/images/photos/Skeena/day02/images/AR_143.jpg http://img-fan.theonering.net/rolozo/images/howe/oldwillow.jpg
DM in many spheres Galaxy Dynamics Particle Theory Colliders Cosmological Component
Beginnings of HEP • 1869 Periodic table finalized • 1897 e- = electron (UK) • 1910’s proton (UK etc.) • 1932 neutron (UK) • 1932 e+ = positron (cosmic rays -- CA) • 1936 m - Whoa! - (c. rays – CO and Panama ) • 1947 p (c. rays – Pic du Midi, France and Chacaltaya, Bolivia (!) ) • 1947 Kaon (c. rays – Mt. Wilson, CA) • 1947 Lambda (c. rays – UK) [ By 1932: quite neat, tidy picture of three basic particles that explained everything in the Universe people had seen up to that point] http://nssdc.gsfc.nasa.gov/image/astro/hst_ngc3314_0014.jpg • http://www.physicscentral.com/action/2000/images/antimatter-img2.jpg
More and More Particles • 1956 Electron neutrino (reactor – WA, GA) • 1950’s: Many, many more particles seen Picture has become complicated!! • 1960’s: Quark theory proposed • Late 1960’s: Quarks confirmed (SLAC) Known by late 60’s Known by late 60’s
Finally: the “congealing” of the SM (The Standard Model) • Late 60’s: Electroweak theory combines QED (Quantum Electrodynamics) and Fermi theory of weak interactions • Also late 60’s: quarks + gluons = QCD (Quantum Chromodynamics) • 1970’s-1990’s: all other predicted SM particles tracked down (c,b,t quarks / t,n_t / g; W+, W- ,Z0 force carriers) • The only “new” particles fit as an extra generation into the already existing theory “1974 November Revolution” Known by late 60’s Known by late 60’s Found 70’s-90’s
By 1994: We Knew the Basic Constituents of ALMOST Everything in the SM Force exchange carriers: Matter particles: • Only one particle remains: the elusive Higgs Boson :
(My Thesis Particle!) Building up from the blocks Both are Hadrons • How to make up hadrons from quarks • Now we see it’s back to being simple!
Why we know quarks are real • Quarks can never be isolated freely!! • But instead of an isotropic distribution of final state particles, we see jets = directions of original quarks • The two pictures are from 2-jet events at Aleph from LEP (CERN [“Where the Web was born” :-> ]) • Jets are one of the clearest demonstrations of initial state free quarks
The Higgs Mechanism and Cocktail Parties • Analogy: the people “crowd around” a speaker giving her “mass” and slow her down • Her “mass” is proportional to her popularity – different for different individuals • The Higgs field fills all space, yet is difficult to understand and find! • Analogy with dark energy (field)..?! • Higgs is sometime called the “God Particle”, tongue-in-cheekily http://www.hep.ucl.ac.uk/~djm/higgsa.html
Known Unknowns in the SM • What do we know, and not know, in the SM? • Know contents: Exchange bosons + fermions + Higgs mechanism • Don’t know if a single Higgs scalar is responsible for the Higgs mechanism Full set of 18 SM Parameters: (NB: Strong CP Problem ignored Here) We know every single parameter (quite well) – except for is what determines the HIGGS MASS (as )
Unknowns Example: Elementary Particles and Masses top quark anti-top quark ne nm nt e-mt u d s c b . . . . Z W+, W- gluons “Crazy” Huge Mass!! ( Mass proportional to area shown: proton mass = ) Why are there so many? Where does mass come from? (Slide credit: Y.K. Kim)
Observed particle level diagram: q c q p n Better understood: Extracting V_cb from B->D*l n Decay (i.e. probing the B Meson Wavefunction) CKM Matrix Goal: Measure precisely one of the fundamental SM parameters (V_cb) (measures amount of quark b to c mixing) Look at one specific decay -- quark level diagram: “hadronization”
B0 Wavefunction impact on V_cb • Contribution to systematic error on V_cb from Form Factors (the largest source) went down from 2.7 to 0.5% Previous Rough Measurement that went into our MC (“SP4”) (CLEO is at Cornell)
[Our secondary goal: checking QCD models through probing B meson Wavefunction – (specifically: Heavy Quark Effective Theories) – everything checked out just fine :-> ]
c2/ c2 c2 c2/dof= 17.9 / 9 c2/dof= 7.3 / 9 (Bbr = Babar experiment at SLAC)
Knowns Example: Experimental Constraints on “Unitarity Triangle” Many many decay modes and thousands of human-years represented here: and everything fits The triangle closes and all the bands overlap – the SM is too good! No significant deviations seen in any decay! Our measurement was critical for the length of this side
Unknowns: Back to Incompleteness of SM • Neutrino Masses not in Minimal SM • Everything else fits so far -- but 18 Parameters not explained GUTs? SUSY? String Theory? XD? Something Else? • Theoretical issues: Hierarchy problem etc. • No allowance for DM (let alone DE) • WHAT is DM?! (i.e. the Dark Side of the Universe) – who is behind the mask??!
Massive n’s in HEP and Cosmo • The low mass n’s are known to be a small component total Universe matter density from cosmological (structure formation) constraints • But heavy mass right-handed n’s may well be some component of the DM ??
DM and GUTs • Massive n’s not accounted for in SM • But they generically fit very well into GUTs – the Holy Grail of HEP • Would be nice to see this…! But we are “only” here, currently
LHC • Most extensions of SM predict more particles at LHC (Large Hadron Collider) • LHC: collide 2 p's together at 14 TeV = 7 times Fermilab CM energy • May find DM candidates • [ Atlas zoom-in and collision clips ]
A Most Amazing Moment for HEP • After nearly 40 years of waiting – HEP may be in for a wild ride • Could see: 1. Nothing 2. one Higgs only, 3.Signature of one of the worked out extensions or.. • 4. Something new • Could: be within first few weeks. • Or several years down the road • Seeing DM candidate would once again complete the Astro-HEP cycle
Precision Measurement Constraints Point to a low mass Higgs • Multiple Electroweak precision measurements are pointing to a low mass Higgs if it’s a single SM particle • If not – we still strongly believe we will see signals of whatever is the Electroweak Symmetry Breaking mechanism is below 1 TeV – i.e. within the LHC reach.
Looking back in time: with accelerators and telescopes! E = mc2 Larger Aperture Accelerators Inflation Big Bang Telescopes Telescopes (Slide credit: Y.K. Kim)
Shifting gears to the Large(Or:a very short history of cosmology) • Humans found: Planets Stars Galaxies Hubble Expansion • DM was known of since Zwicky, but not fully accepted until the 70’s • Known by late 80’s that DM didn’t make =1 • Yet a flat =1 Universe was observed more and more clearly. • DE had always been an options as making up the rest of the 70% of -- but it was “unpalatable” (Kolb+Turner) • Only in the late 90’s did SN observations convince people CFHT, 2005
Some Types of Cosmological Observables • Galaxy clusters / BAO : correlations [E.Rozo] • BBN: IGM and stellar spectra [G. Steigman, M. Pinsonneault, T. Walker, V.Simha] • CMB: affects most cosmic parameters • Cosmic Rays: DM sources? [J. Cairns, H. Yuksel, M. Kistler, G. Mack] • SN: expansion history [J. Beacom , J. Prieto] • Weak and Strong Lensing: galaxy clusters and cosmological [Chris K., M. Peeples, P.Martini, J.Yoo, D. Weinberg, MSSG] [ NB: NOT a comprehensive listing of all work related to cosmology at OSU, only A few examples here! Many other people have done related work!]
LCDM Cosmological Parameter Set • Goals are similar to SM: describe full picture with a few parameters • But still in the infancy, not so well defined – e.g. whether the parameters for inflation should be used • But the minimal set people usually use is: “Vanilla” params: {_ ≈ 0.75, _m ≈ 0.25, _b ≈ 0.05, H_0 ≈ 70 km /s/ Mpc, Σm_n <~ 1eV , w≈ 1 , } Extra: {s_8 ≈0.9 f_nu, _k, r, n_s, z_reion, tau_reion , w_a etc. }
Table of the Cosmological Parameters Still much uncertainty in what parameters to use in fits -This indicates it is unclear just what set should be used… not as well-defined yet as the SM
Neutrino Masses: -LL on at least one: 0.05 eV We will likely know The neutrino masses Within 10 yrs..! photons neutrinos Λ cdm m3=0.05 eV baryons m2=0.009 eV m1≈ 0 eV Evolution of the background densities: 1 MeV → now -UL on Σm_n <~ 1eV Ωi= ρi/ρcrit (Slide credit: S. Pastor)
Basic Weak Lensing Geometry Mass Profile of Lens Deflection Angle: (Narayan+Bartelmann, 1997)
Observer Lensing mass Source Analogy to Probing the Insides of a Hadron • Translate to mass profile – can analogize to extracting form factor (~wavefunction) of a hadron) Contains Mass Profile Information
Lensing Effect on Background Galaxies Foreground Cluster Background Source shape Note: the effect has been greatly exaggerated here (Orig Figure: S.Dodelson)
Simulations of COWL (Cosmological Weak Lensing) • Field on the right has higher _m (Orig Figure: S.Dodelson)
Several Upcoming COWL Surveys Panstarrs Dark Energy Survey LBT-OWLS SNAP LSST ? OSU (Orig Figure: S.Dodelson)
Photometric Redshift • We may ultimately use several bands to obtain zp estimates and increase weak lensing signal • But so far, in the Winter Run it looked unpromising to use 3 band information for this – better to get more clusters and source galaxies [Dec 2 update : see next page!]
Use Photometric Redshift to Strengthen Lensing Signal ? Number of galaxies • From HyperZ (photoZ code): # of entries vs. zp3-zp5 • Where: zp3 = 3-band photoZ, zp5 = 5-band photoZ • Looks promising potentially, but we found only about 60% of zp3<0.3 matched zp5<0.3, which would not strengthen our weak lensing signal dramatically • So we are not planning for the Winter run to do 3 band observing • [ Update: Dec 2 – new work by P. Martini indicates it may in fact be useful, so we will use 3 bands! ] zp3 – zp5 [Thanks for discussions to: N. Morgan, R. Assef]
z = 7 dark matter z = 5 z = 3 time z = 0.5 z = 0 z = 1 CLWL (Cluster Weak Lensing) • We can determine some of the LCDM params from CLWL, using • 1. Total Mass of cluster at a given z • 2. Radial mass profiles 5 Mpc Kravtsov
LBT OWLS Projections • Projections for LBT with several clusters by next Autumn Assumes lensing using 50 richest clusters in observed 250 degree squared field with all background (lensed) galaxies at z=0.6 Colors are 1,2,3 sigma countours Here: sigma_8 vs. Omega_m (Plot: J. Yoo) We may be getting first data as early as JANUARY – need full weak lensing pipeline set up by then – this is my priority at the moment!
Other Parameters from OWLS (Plot: J. Yoo) Here: w vs. Omega_m and w vs. sigma_8
DES Projection for Sky Coverage Blanco 4-m Optical Telescope at CTIO: 5000 sq. deg. Dark Energy Survey (Fig: J.Frieman)
Summing Up: HEP + Cosmology makes a “power duo” • We are entering a bold new era: where “Large” is the name of the game • Potential to make progress on some of the fundamental questions of our time • LHC and LBT+friends both have profound potential to reveal a whole new level of information about our Universe • Dream Big, friends. :-> • [ CMS construction video ]
END! • Go to backup slides……………..
QEDL: All chemistry, Solid state physics And much of astrophysics: QCD L : Nuclear physics, Neutron stars, etc. : SM Math Simplified 1: QED & QCD Parts – “easy” part • We will list only type 3 (interaction) terms – all cyan circles surround couplings known i.t.o. basic SM parameters
SM Math Simplified 2: Electroweak Part: matter • Next: Electroweak theory of fermions (l,n,q) and spin-1 bosons (W+, W-, Z) Wolfenstein Form of CKM Matrix:
All functions of Known SM params: (NB: Strong CP Problem ignored Here) All 18 SM Params: SM Math Simplified 3: Electroweak Part: with Higgs We know every single parameter (quite well) – except for is what determines the HIGGS MASS (as )
Collider Level Diagram B0 Meson positron 50% Matter50% Anti-Matter electron Anti-B0 Meson
General Categories of HEP Experiments • Accelerator-based: [e, p], n, m, n • Collider and fixed-target • Non-accelerator: proton decay, neutrinoless double beta decay • Cosmic-ray: charged particles • Cosmic-ray: neutrinos