Αστροσωματιδιακή Φυσική, πείραμα CAST για την ανακάλυψη σκοτεινής ύλης στο CERN

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1 Αστροσωματιδιακή Φυσική, πείραμα CAST για την ανακάλυψη σκοτεινής ύλης στο CERN Χρήστος Ελευθεριάδης Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης

2 Αστροσωματιδιακή Φυσική Κοσμολογία Αστρονομία-αστροφυσική Φυσική στοιχειωδών σωματιδίων ((χωρίς σειρά...)

3 Αστροσωματιδιακή Φυσική Η Κοσμολογία μελετά το Σύμπαν ως σύνολο Το Σύμπαν γεννήθηκε (?) με μια Μεγάλη Έκρηξη (Big B Bang) Με θερμοκρασία και πυκνότητα οι οποίες, προϊόντος του χρόνου, έβαιναν μειούμενες.. Υπό τις συνθήκες αυτές, καλή η ΓΘΣ, αλλά θα θέλαμε μια κβαντική θεωρία για τη βαρύτητα (που δεν την έέχουμε ακόμα...) Αχαριστία... Η θεωρία της ΜΕ (που δεν θα έπρεπε να τη λέμε έκρηξη..) βασίστηκε στη ΓΘΣ και στην κοσμολογική αρχή (η κατανομή της ύλης είναι ομογενής και ισοτροπική).

4 Κοσμολογία-ΦΣΣ Τις πρώτες στιγμές μετά τη Μ.Ε., σύμπασα η ύλη του Σύμπαντος ήταν μια «σούπα» στοιχειωδών σωματιδίων.....πράγμα που συνδέει το κοσμολογικό πρόβλημα της περιγραφής του Σύμπαντος στις πρώτες και ίσως πιο σημαντικές στιγμές του, με τη Φυσική Στοιχειωδών Σωματιδίων.. Πηγαίνοντας πίσω στο χρόνο, φτάνουμε στο χρόνο του Planck (10-43 sec) και δεν μπορούμε ούτε θεωρητικά πλέον να μιλάμε για την τότε κατάσταση του Σύμπαντος. Η πιο «επεξεργασμένη» θεωρία που έχουμε για την κβαντική βαρύτητα, είναι η θεωρία χορδών (strings)..

5 ΚΒΑΝΤΙΚΗ ΒΑΡΥΤΗΤΑ Θεωρία υπερχορδών? (με ερωτηματικό..) Δεν υπάρχει σήμερα θεμελιωμένη θεωρία για κβαντική βαρύτητα.. Η Γενική θεωρία της σχετικότητος είναι μία καλή μεν, κλασική δε, θεωρία για την βαρύτητα. Αντιμετωπίζει την βαρύτητα ως συνέπεια της διαταραχής του χώρου από την παρουσία μάζας-ενέργειας....καμμία σχέση με την εικόνα δυνάμεων ανταλλαγής που έχουμε για τις άλλες αλληλεπιδράσεις

6 interaction Mediating Spin Range boson Electromag Photon netic 1 Long Weak W+, W-, Z0 1 Very short Strong gluons 1 Effectively short ( (confinement) gravitational Graviton ( (?) 2 Long

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8 COBE Cosmic Background Explorer

9 Σημεία Lagrange Σύστημα Ηλιου-Γης

10 Τροχιά του WMAP

11 Ανισοτροπία ΚΑΜ Είναι ελάχιστη, μικρότερη από ένα μέρος στα χίλια

12 Big Bang Nucleosynthesis

13 SOHO (στο L1) S Solar and Heliospheric Observatory 1500 κομήτες Ηλιοσεισμολογία

14 SOHO Coronagraph Solar Corona problem

15 HESS High Energy Stereoscopic System

16 HESS Το σύστημα κατόπτρων του HESS

17 HESS H.E.S.S. puts limits on the energy dependence of the speed of light A search for a dark matter annihilation signal towards the Canis Major overdensity with H.E.S.S H.E.S.S. Observations of the Prompt and Afterglow Phases of GRB B Discovery of gamma-ray emission from the shell-type supernova remnant RCW 86 with H.E.S.S

18 SWIFT Swift Gamma-ray Burst Mission

19 GRB B 12.8 εκατομμύρια έτη φωτός μακρυά... z=6.7!!!!

20 Red shift z=δλ/λ Γραμμές απορρόφησης μετατοπισμένες..

21 GRB080319B Ορατός διά γυμνού οφθαλμού δισεκατομμύρια έτη φωτός μακρυά...

22 Nestor Πύλος...

23 Nestor tower Neutrino astronomy

24 Συστοιχία πύργων στο NESTOR Ανακατασκευή γεγονότος

25 Neutrino physics and astronomy AMANDA ICE CUBE ANTARES BAIKAL KAMIOKANDE MINOS... KM3

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27 Dark matter: a lot of candidates Relativistic particles cannot be controlled by gravity rotation curves cannot be explained in terms of HDM Hot dark matter, like neutrinos (not a strong o one..) Cold dark matter (this is the strong c candidate..) WIMPS (~3 PhDs per parameter may be m more) Neutralino LSP MACHOs and last but not least

28 The STRONG CP PROBLEM Possible CP-violating term in QCD lagrangian: ( ) Experimental consequence: prediction of electric dipole moment for the neutron: (A = ) BUT experimental result... So, Arg det M ((QCD vacuum + EW quark mixing)

29 A brief history of axion The strong CP violating term can be suppressed easily! You just need a massless quark! no quark is massless.. A solution proposed by Peccei and Quinn: new global chiral U(1) symmetry spontaneously broken at scale fα θ is not anymore a constant, but a field the axion a a(x) Broken symmetry Goldstone theorem Appearance of a spinless particle Nambu-Goldstone boson (axion) If symmetry is perfect massless However, for some reason, no symmetry is perfect in this world axions acquire a small mass

30 Axions may occur in two flavors: Standard (Peccei-Quinn) Axion: similar to very light neutral pion (π0) rest mass ~ ev/c2 lifetime much longer than the age of the Universe Kaluza-Klein (KK) Axions: predicted by recent theories of extradimensions, proposed as extensions of the Standard Model mass spectrum of all the excited Kaluza-Klein states extends up to ~ 10 kev / c2 relative shorter lifetime: τ ~ m-3 The axion-photon-photon coupling constant gαγγ is the same for both types

31 Neutrinos from the Sun Reactionchains Helium Energy 26.7 MeV Solar radiation: 98 % light 2 % neutrinos At Earth 66 billion neutrinos/cm2 sec Hans Bethe (born 1906, Nobel prize 1967) H Thermonuclear reaction chains (1938) T

32 Sun Glasses for Neutrinos? 8.3 light minutes 1000 light years of lead needed to shield solar neutrinos Bethe & Peierls 1934: this evidently means that one will never be able to observe a neutrino.

33 Axion summary Axions are predicted to have no charge, 106 GeV ma = 6 ev very low mass, fa spin-parity 0 very low interaction cross-sections They are nearly invisible to ordinary matter excellent candidates for dark matter a necessary component of string theory

34 Where the Axions come from Cosmological C axions (cold dark matter) Solar axions Stellar plasmas may be a powerful source of axions.. Important notice: The closest stellar plasma available is: the Sun

35 Primakoff effect Axions are coupled to two photons This could be done either in the sun interior or in earth a thermal photon converts into an axion in the Coulomb fields of nuclei and electrons in the solar plasma The axion converts into a photon under a strong magnetic field in the laboratory (inverse process, Sikivie 1983) S

36 Solar axion flux ((with new solar model implemented)

37 Christos Eleftheriadis CERN LHC

38 CAST: magnet & infrastructure Decommissioned LHC test dipole magnet. Superconducting, operation at T=1.8 K. Magnetic field: B=9T. Electric current 13,000 A. Length: L=9.26m. Rotating platform ( Vertical: ±8, Horizontal: ±40 ) 3 X-ray detectors X-ray Focusing Device

39 Sun Filming Twice a year (September and March): filming the Sun through the window Regular checks by CERN surveyors

40 TPC Position sensitive ((3mm spacing) Clean materials + shielding (polyethylene+copper+ancient lead)) NO SHIELDING SHIELDING 448 anode wires(x) 996 cathode wires(y) c/kev/sec/c m c/kev/sec/cm2 SHIELDING + N2 FLUX c/kev/sec/cm2 Lower Background from 2003 to 2004 data by more than a factor of two

41 Micromegas Micromegas Plot with data from PANTER X-Ray detection Threshold: ~0.6keV ( (95%Ar+5%Isobutane) Improved background rate: 5*10-5 events kev-1s-1cm-2

42 CCD Excellent Energy Resolution Excellent Space Resolution Pixel size: 150µm x 150µm Additional shield plus X-ray finger source for continuous monitoring of the spot position 2003: 11.5± counts cm-2 s-1 kev : 7.69± counts cm-2 s-1 kev-1 Background reduction by a factor of 1.5

43 The X-Ray Telescope Telescope-Magnet Alignment Space technology: Spare part of the ABRIXAS Space mission

44 The X-Ray Telescope ~35% efficiency due to reflections 50mm 1mm 1.7 m 27 nested pairs of mirrors From 50mm (LHC magnet aperture) to ~1mm signal-to-noise improvement ((up to 200!!!)

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46 Total Effective Area 90 Simulation results Tests at MPE/Panter Effective Area (cm^2) ,5 1 1,5 2 2,5 3 3,5 4 4,5 5 5,5 6 6,5 7 7,5 8 8,5 9 Energy (kev)

47 TPC subtracted spectrum MM subtracted spectrum CCD spectrum Data taking during 2003 and 2004 In total 12 months Result from CAST phase I: g a GeV 1 Submitted to JCAP, hep-ex (2007), CAST Collaboration

48 Submitted to JCAP, hep-ex (2007), CAST Collaboration

49 CAST phase II Exploring higher axion masses... Coherence for higher masses may be restored by using buffer gas. Filling the two magnetic channels with helium The photon acquires an effective mass: mγ > 0 Momentum transfer is (as opposed ) to Coherence condition (ql<< 1) is recovered for a narrow mass range around mγ

50 CAST phase II mγ can be adjusted by changing the gas pressure: Every specific pressure of the gas allows the test of a specific axion mass. The higher the pressure, the higher the photon effective mass, the higher the axion mass tested. For every step there is a new discovery potential!

51 Transforming to Phase II Cold Windows (installed) /He-Gas System 4 He gas system (in operation in 2005 and 2006) H High precision (better than 0.01 mbar) H He pressure =13.43 mbar ma~ 0.39 ev/c2 4 3 He system responsibility of AUTh team Sunrise micromegas data and analysis AUTh

52 Ongoing data analysis, no limits derived yet. Region explored with He4 First time a helioscope explores the models region Current status: upgrade to He3 phase, extending sensitivity up to 1 ev axion mass (135.8 mbar). Add X-ray focusing device in the Micromegas line

53 Constraints Astrophysical Our sun Globular clusters White dwarfs Supernova 1987A all the above related to the energy loss argument Cosmological Overclosure of Universe Experimental Helioscope experiments with magnets Experiments with crystals

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59 General considerations on dark matter there are many indications that dark matter exists in the Universe if dark matter exerts gravity, then it should also be subject to gravity what is the deepest gravitational well in our local environment? if dark matter contains non-relativistic particles (CDM), then these should accumulate in gravitational wells if dark matter particles decay into photons, then we should see a halo around the Sun is there any halo-like structure around the Sun which we do not understand? The Sun! Yes!!

60 The solar corona problem corona visible during total solar eclipses identified as a solar phenomenon in the middle of the 19th century before: terrestrial smoke, lunar atmosphere (Kepler, Halley) a temperature > 106 K 2003: physical origin of the coronal heating still not understood total solar eclipse 3 Nov 1994 Chile

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62 SUPERNOVAE IA A SN Ia is the thermonuclear explosion of a carbon-oxygen white dwarf in a binary when the rate of mass transfer from the companion star is high. ((Calal/Tololo Sample, Kim et al. 1997) SNe IA as cosmological standard candles. The peak luminosity of SNe IA can be used as an efficient distance indicator. Alessandro Mirizzi Joint ILIAS-CAST-CERN Axion Training

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65 Type I (puzzle?) - a binary model (red giant and white dwarf) where the accreted mass is so high it pushes the white dwarf over the chandrashekar limit. The core collapses igniting the carbon in one big burst. The star blows itself to bits and no remnant remains.

66 HUBBLE DIAGRAM Supernova Ia as cosmological standard candles Accelerated expansion (Ω M = 0.3, Ω Λ = 0.7) 0 Decelerated expansion (Ω M = 1) 1 SNe Ia at 0.3 z 1.7 appear fainter than expected for a decelerating Universe

67 CONSTRAINTS ON PHOTON AXION CONVERSION FROM CMB Photon-axion conversion should leave their imprint on background (CMB) photons. the cosmic microwave Appreciable distrortions to the blackbody spectrum of the CMB may appear, considering that CMB data are have an accuracy of one part on FIRA S COBE Supernova dimming by photon axion conversion?.. satelli te

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70 CONCLUSIONS There are some problems to be answered (related to axions) 3. Strong CP problem 4. Dark matter 5. Solar corona 6. The PVLAS result (done..) For the time being, CAST established the most stringent experimental limit on axion coupling constant, exceeding for the first time astrophysical constraints. CAST phase II is currently exploring an experimentally unexplored axion mass - coupling constant region predicted by axion models

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