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INCONTRI DI FISICA, LNF, 9 OTT. 2009. L’ UNIVERSO INVISIBILE: IL PROBLEMA DELLA MATERIA ED ENERGIA OSCURE. Antonio Masiero Univ. di Padova e INFN, Padova. UNIFICAZIONE delle INTERAZIONI FONDAMENTALI. IL MODELLO STANDARD PARTICELLARE. WHY TO GO BEYOND THE SM. “OBSERVATIONAL” REASONS.
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INCONTRI DI FISICA, LNF, 9 OTT. 2009 L’ UNIVERSO INVISIBILE:IL PROBLEMA DELLAMATERIA ED ENERGIA OSCURE Antonio Masiero Univ. di Padova e INFN, Padova
WHY TO GO BEYOND THE SM “OBSERVATIONAL” REASONS THEORETICAL REASONS • INTRINSIC INCONSISTENCY OF SM AS QFT • (spont. broken gauge theory • without anomalies) • NO ANSWER TO QUESTIONS THAT “WE” CONSIDER “FUNDAMENTAL” QUESTIONS TO BE ANSWERED BY “FUNDAMENTAL” THEORY • (hierarchy, unification, flavor) • HIGH ENERGY PHYSICS • (but AFB……) • FCNC, CP • NO (but b sqq penguin …) • HIGH PRECISION LOW-EN. • NO (but (g-2) …) • NEUTRINO PHYSICS • YE m0, 0 • COSMO - PARTICLE PHYSICS • YE (DM, ∆B cosm, INFLAT., DE) Z bb NO NO NO NO YES YES YES
INDICAZIONI DI NUOVA FISICA AL DI LA’ DEL MODELLO STANDARD PARTICELLARE • MASSA DEI NEUTRINI • ESISTENZA DI MATERIA OSCURA NON COSTITUITA DALLA “SOLITA” MATERIA (protoni, neutroni) • ASIMMETRIA COSMICA TRA MATERIA E ANTIMATERIA: ESISTENZA DI UNA NUOVA SORGENTE DI VIOLAZIONE DI CP OLTRE A QUELLA PREVISTA DAL MODELLO STANDARD • IMPOSSIBILITA’ NEL MS DI OTTENERE UNA FASE INFLAZIONARIA ( ESPANSIONE ACCELERATA ESPONENZIALMENTE ) NELL’UNIVERSO PRIMORDIALE • DOMANDE “FONDAMENTALI” A CUI IL MODELLO STANDARD NON RISPONDE: - UNIFICAZIONE DELLE FORZE FONDAMENTALI - MASSE E MESCOLAMENTI DEI FERMIONI - “STABILITA’” DELLA SCALA DI ENERGIA A CUI I BOSONI W e Z PRENDONO MASSA ( circa 100 GeV)
THEORETICAL REASONS TO GO BEYOND THE SM • FLAVOR PUZZLE RATIONALE FOR FERMION MASSES AND MIXINGS • UNIFICATION PROBLEM NO REAL UNIF. OF ELW.+STRONG INTERACTIONS +GRAVITY LEFT OUT OF THE GAME • HIERARCHY PROBLEM(S) ULTRAVIOLET COMPLETION OF THE SM TO (NATURALLY) STABILIZE THE ELW. BREAKING SCALE + TUNING OF THE COSMOLOGICAL CONSTANT
Present “Observational” Evidence for New Physics • NEUTRINO MASSES • DARK MATTER • MATTER-ANTIMATTER ASYMMETRY • INFLATION
MICRO MACRO PARTICLE PHYSICS COSMOLOGY HOT BIG BANG STANDARD MODEL GWS STANDARD MODEL HAPPY MARRIAGE Ex: NUCLEOSYNTHESIS POINTS OF FRICTION BUT ALSO • COSMIC MATTER-ANTIMATTER ASYMMETRY • INFLATION • - DARK MATTER + DARK ENERGY “OBSERVATIONAL” EVIDENCE FOR NEW PHYSICS BEYOND THE (PARTICLE PHYSICS) STANDARD MODEL
The Energy Scale from the“Observational” New Physics neutrino masses dark matter baryogenesis inflation NO NEED FOR THE NP SCALE TO BE CLOSE TO THE ELW. SCALE The Energy Scale from the “Theoretical” New Physics Stabilization of the electroweak symmetry breaking at MW calls for an ULTRAVIOLET COMPLETION of the SM already at the TeV scale+ CORRECT GRAND UNIFICATION “CALLS” FOR NEW PARTICLES AT THE ELW. SCALE
LE “COSTANTI” DI ACCOPPIAMENTO FONDAMENTALI NON SONO COSTANTI
DA G.U.T. A SUSY G.U.T. Aggiunta di nuove particelle SUSY partner di quelle ordinarie del Modello Standard ad una scala di massa tra 100 e 1000 GeV
MODIFICARE LA GRAVITA’ (MOND) • DM e’ sempre derivata dalle osservazioni assumendo lavalidita’ della legge standard della gravita’ possibile evitare l’introduzione di DM se modifico la legge di gravita’ su varie scale astronomiche • Possibili problemi per CDM • Fit di MOND a >100 curve di rotazione galattiche con successo • Problemi a riprodurre i dati relativi alla dinamica di clusters: necessita’ di introdurre materia invisibile (neutrini, barioni oscuri) • Versione relativistica di MOND ( Tensor-Vector Scalar Th. - TeVeS) + covarianza ( Bekenstein ’04, Sanders ’05) • TeVeS : OK per strong lensing, invece necessita di materia invisibile per riprodurre il weak lensing. Barioni oscuri necessari anche per fenomeni quali il Bullet Cluster ( Milgrom ’08)
The BULLET CLUSTER: two colliding clusters of galaxies Stars, galaxies and putative DM behave differently during collision, allowing for them to be studied separately. In MOND the lensing is expected to follow the baryonic matter, i.e. the X-ray gas. However the lensing is strongest in two separated regions near the visible galaxies most of the mass in the cluster pair is in the form of collisionless DM
La conoscenza che abbiamo riguarda solo il 4% dell’Universo il resto è ancora ignoto !!
Inventario della materia nell’ Universo 1% Stelle 7% Gas nelle galassie materia barionica 7% Gas materia non barionica 85% Materia Oscura
Albert Einstein (1879-1955) Equazione del Campo di Gravitazione Costante Cosmologica LA COSTANTE COSMOLOGICA SORGENTE DELL’ENERGIA OSCURA DELL’UNIVERSO E CAUSA DELLA SUA ESPANSIONE ACCELERATA?
Bilancio energetico dell’Universo ? PROBLEMA DELL’ENERGIA DEL VUOTO O DELLA COSTANTE COSMOLOGICA
IS THE FINE-TUNING A REAL PROBLEM? • WARNING: THERE EXISTS AN EVEN “LARGER” HIERARCHY OR FINE -TUNING OR NATURALNESS PROBLEM: THE COSMOLOGICAL CONSTANT PROBLEM (“ THE MOTHER” OF ALL NATURALNESS PROBLEMS); SO FAR, WE SIMPLY “ACCEPT” SUCH FINE-TUNING! • (OUTRAGEOUS) POSSIBILITY: THE “THEORY OF EVERYTHING” COULD BE UNIQUE, BUT WITH MANY (INFINITE?) VACUA EACH GIVING RISE TO A DIFFERENT UNI-VERSE ( MULTI-VERSE POSSIBILITY).WE CAN LIVE ONLY IN THE VERY RESTRICTED CLASS OF THE “MULTI-VERSE SPACE” WHERE THE “BOUDARY CONDITIONS” ( FOR INSTANCE, THE VALUE OF THE COSMOLOGICAL CONSTANT OR THE SCALE OF THE ELW.SYMMETRY BREAKING AND, HENCE, THE HIGGS MASS) EXHIBIT VALUES ALLOWING FOR THE CORRECT BBN, LSS,… OUR LIFE! ANTHROPIC PRINCIPLE
UNI -- VERSOOMULTI -- VERSO • Tutta l’evoluzione dell’Universo (asimmetria tra materia ed antimateria, nucleosintesi, formazione delle galassie, ammassi, etc., sistema solare, vita sulla Terra etc.) dipende in maniera molto stretta dal preciso valore assunto da alcuni parametri fondamentali ( tra questi quello della costante cosmologica): e’ possibile che quello in cui noi siamo sia solo uno dei moltissimi –versi ( MULTI – VERSO) ?
DM NEW PHYSICS BEYOND THE ( PARTICLE PHYSICS ) SM - if Newton is right at scales>size of the Solar System • ΩDM= 0.233 ± 0.013 * • Ωbaryons = 0.0462 ± 0.0015 ** *from CMB ( 5 yrs. of WMAP) + Type I Supernovae + Baryon Acoustic Oscillations (BAO) **CMB + TypeI SN + BAO in agreement with Nucleosynthesis (BBN)
LA MATERIA OSCURA E’ QUANTITATIVAMENTE E QUALITATIVAMENTE LA PIU’ IMPRESSIONANTE EVIDENZA DI NUOVA FISICA OLTRE IL MS PARTICELLARE • QUANTITATIVE: Taking into account the latest WMAP data which in combination with LSS data provide stringent bounds on DM and BEVIDENCE FOR NON-BARYONIC DM AT MORE THAN 10 STANDARD DEVIATIONS!!THE SM DOES NOT PROVIDE ANY CANDIDATE FOR SUCH NON-BARYONIC DM • QUALITATIVE: it is NOT enough to provide a mass to neutrinos to obtain a valid DM candidate; LSS formation requires DM to be COLD NEW PARTICLES NOT INCLUDED IN THE SPECTRUM OF THE FUNDAMENTAL BUILDING BLOCKS OF THE SM !
SONO I NEUTRINI LA MATERIA OSCURA?SIC TRANSIT GLORIA MUNDI • Massive neutrinos: only candidates in the SM to account for DM. From here the “prejudice” of neutrinos of a few eV to correctly account for DM • Neutrinos decouple at ~1 MeV ; being their mass<<decoupling temperature, neutrinos remain relativistic for a long time. Being very fast, they smooth out any possible growth of density fluctuation forbidding the formation of proto-structures. • The “weight” of neutrinos in the DM budget is severely limited by the observations disfavoring scenarios where first superlarge structures arise and then galaxies originate from their fragmentation
m = 0 eV m = 1 eV (E..g., Ma 1996) m = 7 eV m = 4 eV LSS PATTERN AND NEUTRINO MASSES
Cosmological Bounds on the sum of the masses of the 3 neutrinos from increasingly rich samples of data sets
LA MATERIA OSCURA QUALE CHIAVE DI ACCESSO ALLA NUOVA FISICA OLTRE IL MS: PUO’ LA PARTICELLA DI MATERIA OSCURA ESSERE IL PRIMO SEGNALE DELLA NUOVA FISICA ALLASCALA ELETTRODEBOLE?
THE “WIMP MIRACLE” Bergstrom Tante le possibilita’, ma gli WIMP sono speciali : singolare coincidenza tra param. dei MODELLI STANDARD PART. e COSM. per dare validi candidati di DM proprio alla scala eletttrodebole (TeV)
WIMPS (Weakly Interacting Massive Particles) # exp(-m/T) # does not change any more #~# m Tdecoupl. typically ~ m /20 depends on particle physics (annih.) and “cosmological” quantities (H, T0, … 10-3 h2_ COSMO – PARTICLE CONSPIRACY ~ <(annih.) V > TeV2 From T0 MPlanck ~ 2 / M2 h2 in the range 10-2 -10-1 to be cosmologically interesting (for DM) m ~ 102 -103 GeV (weak interaction) h2 ~ 10-2 -10-1 !!! THERMAL RELICS (WIMP in thermodyn.equilibrium with the plasma until Tdecoupl)
HOW TO COPE WITH THE HIERARCHY PROBLEM • LOW-ENERGY SUSY • LARGE EXTRA DIMENSIONS • DYNAMICAL SYMMETRY BREAKING OF THE ELW. SYMMETRY • LANDSCAPE APPROACH (ANTHROPIC PRINCIPLE)
STABLE ELW. SCALE WIMPs from PARTICLE PHYSICS SUSYEXTRA DIM. LITTLE HIGGS. 1) ENLARGEMENT OF THE SM (x, ) (x, ji) SM part + new part Anticomm. New bosonic to cancel 2 Coord. Coord. at 1-Loop 2) SELECTION RULE DISCRETE SYMM. STABLE NEW PART. R-PARITY LSP KK-PARITY LKP T-PARITY LTP Neutralino spin 1/2 spin1 spin0 mLSP ~100 - 200 GeV * mLKP ~600 - 800 GeV 3) FIND REGION (S) PARAM. SPACE WHERE THE “L” NEW PART. IS NEUTRAL + ΩL h2 OK mLTP ~400 - 800 GeV * But abandoning gaugino-masss unif. Possible to have mLSP down to 7 GeV Bottino, Donato, Fornengo, Scopel
SUSY & DM : a successful marriage • Supersymmetrizing the SM does not lead necessarily to a stable SUSY particle to be a DM candidate. • However, the mere SUSY version of the SM is known to lead to a too fast p-decay. Hence, necessarily, the SUSY version of the SM has to be supplemented with some additional ( ad hoc?) symmetry to prevent the p-decay catastrophe. • Certainly the simplest and maybe also the most attractive solution is to impose the discrete R-parity symmetry • MSSM + R PARITYLIGHTEST SUSY PARTICLE (LSP) IS STABLE . • The LSP can constitute an interesting DM candidate in several interesting realizations of the MSSM ( i.e., with different SUSY breaking mechanisms including gravity, gaugino, gauge, anomaly mediations, and in various regions of the parameter space).
WHO IS THE LSP? • SUPERGRAVITY ( transmission of the SUSY breaking from the hidden to the obsevable sector occurring via gravitational interactions): best candidate to play the role of LSP: NEUTRALINO ( i.e., the lightest of the four eigenstates of the 4x4 neutralino mass matrix) In CMSSM: the LSP neutralino is almost entirely a BINO
WHICH SUSY HIDDEN SECTOR SUSY BREAKING AT SCALE F F = (105 - 106) GeV F = MW MPl GRAVITY GAUGE INTERACTIONS MESSENGERS Mgravitino~ F/MPl ~ (102 -103) eV Mgravitino ~ F/MPl ~ (102 -103) GeV OBSERVABLE SECTOR SM + superpartners MSSM : minimal content of superfields
NEUTRALINO LSP IN THE CONSTRAINED MSSSM: A VERY SPECIAL SELECTION IN THE PARAMETER SPACE? Favored by gµ -2 Favored by DM Excluded: stau LSP Excluded by bsγ Ellis, Olive, Santoso, Spanos
After LEP: tuning of the SUSY param. at the % level to correctly reproduce the DM abundance: NEED FOR A “WELL-TEMPERED” NEUTRALINO
MA SIAMO SICURI CHE LA MATERIA OSCURA SIA LEGATA SOLAMENTE A NUOVA FISICA OLTRE IL MODELLO STANDARD PARTICELLARE? • LA PIU’ LONTANA INFORMAZIONE ( AFFIDABILE) CHE ABBIAMO SULLE PRIME FASI DELL’UNIVERSO E’ LA NUCLEOSINTESI ( t > 1 sec. dopo il Big Bang) • PRIMA DELLA NUCLEOSINTESI L’EVOLUZIONE ( ad es. la velocita’ di espansione) DELL’UNIVERSO POTEVA DIFFERIRE SIGNIFICATIVAMENTE DAL QUADRO DELLA COSMOLOGIA STANDARD DEL BIG BANG CALDO CON PROFONDE IMPLICAZIONI SULL’ABBONDANZA E NATURA DELLA MATERIA OSCURA
DM and NON-STANDARD COSMOLOGIES BEFORE NUCLEOSYNTHESIS • NEUTRALINO RELIC DENSITY MAY DIFFER FROM ITS STANDARD VALUE, i.e. the value it gets when the expansion rate of the Universe is what is expected in Standard Cosmology (EX.: SCALAR-TENSOR THEORIES OF GRAVITY, KINATION, EXTRA-DIM. RANDALL-SUNDRUM TYPE II MODEL, ETC.) • WIMPS MAY BE “COLDER”, i.e. they may have smaller typical velocities and, hence, they may lead to smaller masses for the first structures which form GELMINI, GONDOLO
LARGER WIMP ANNIHILATION CROSS-SECTION IN NON-STANDARD COSMOLOGIES • Having a Universe expansion rate at the WIMP freeze-out larger than in Standard Cosmology possible to provide a DM adequate WIMP population even in the presence of a larger annihilation cross-section ( Catena, Fornengo, A.M., Pietroni) • Possible application to increase the present DM annihilation rate to account for the PAMELA results in the DM interpretation (instead of other mechanisms like the Sommerfeld effect or a nearby resonance) El Zant, Khalil, Okada
WIMPs: proviamo a “fabbricarli” anche noi ! L’IPOTESI “WIMPS” MATERIA OSCURA COSTITUITA DA PARTICELLE “NUOVE” CON MASSA TRA 100 E 1000 GEV CHE INTERAGISCONO SOLO DEBOLMENTE LHC, ILC (LINEAR COLLIDER ) POSSONO PRODURRE WIMPS WIMPS scappano dal rivelatore “FIRMA” DELL’HIGGS: ENERGIA MANCANTE DALLA MISURA DI MATERIA OSCURA POSSO RISALIRE A QUANTO GLI WIMPS INTERAGISCANO CON LA MATERIA ORDINARIA E QUINDI PREDIRE LA QUANTITA’ DI WIMPS CHE PRODURRO’ A LHC O A ILC
PREDICTION OF Ω DM FROM LHC AND ILC FOR TWO DIFFERENT SUSY PARAMETER SETS BALTZ, BATTAGLIA, PESKIN, WIZANSKY
HUNTING FOR DARK MATTER INDIRECT DM SEARCHES DIRECT DM SEARCHES
Neutralino-nucleon scattering cross sections along the WMAP-allowed coannihilation strip for tanbeta=10 and coannihilation/funnel strip for tanbeta=50 using the hadronic parameters ELLIS, OLIVE, SAVAGE Ellis, Olive, Sandick LHC Sensitivity