Daniela Kirilova. Institute of Astronomy Bulgarian Academy of Sciences, Sofia, Bulgaria

Transcription

1 ISNP Particle ad Nuclear Astrophysics 22 September 2010, Erice Daiela Kirilova Istitute of Astroomy Bulgaria Academy of Scieces, Sofia, Bulgaria

2 Why explore LA? Cosmology ca be used to probe eutrio properties. Kowledge about LA helps to determie the cosmological parameters Neutrios are abudat, sigificat cosmological effect is expected. There exist cosmological evidece about the presece of additioal relativistic desity - additioal light particles, LA, etc... N BBN = N CMB = N SDS = Combied eutrio oscillatios data (icludig MiiBooe ad LSND) require 1 or 2 additioal sterile eutrio. Active-sterile oscillatios may geerate LA. LA provides relaxatio or ehacemet of BBN costraits o oscillatios. Determiig LA at BBN would test the assumptio that sphaleros equilibrate L ad B asymmetries I case of >2 Plak will be able to detect small eutrio mass ~0.07 ev because LA ehaces the effect of the mass LA chaotic behavior may result i formatio of leptoic domais Ihomogeeous BBN - Abudaces of light elemets may be sesitive to LA magitude ad sig.

3 BBN costraits i the presece of LA

4 Lepto asymmetry of the Uiverse 3 1 T i 3 2 L ( ) i 3 i i 12 (3) T Lepto Asymmetry may be up to 8 orders of magitude larger tha the baryo oe, measured precisely by differet idepedet meas (by BBN ad CMB data, etc.) Though usually assumed L~, big LA may reside i the eutrio sector. (uiversal charge eutrality implies L e =). L~ CNB has ot bee detected yet, hece LA may be measured/costraied oly idirectly through its effect o other processes, which have left observable relics or traces i the Uiverse: Dolgov,2002 light elemet abudaces from Big Bag Nucleosythesis Wagoer et al.1967.terasawa&sato, 1988 Serpico&Raffelt, 2005; Pastor, Pito&Raffelt,2009; Simha&Steigma, 2008 Cosmic Microwave Backgroud Lesgourgues&Pastor,1999; Shiraishi et al., 2009; Popa&Vasile, 2008 LSS, etc. /T ( b ) / ~ 6.10 b L ( l ) / 10 l L i i

5 Iformatio form differet epochs LHC ly BBN CMB Reach of cotemporary telescopes

6 Lepto asymmetry of the Uiverse Lepto Asymmetry L ( l ) / may be up to 8 orders of magitude larger tha the baryo oe, l ( b ) / ~ 6.10 b 10 measured precisely by differet idepedet meas (by BBN ad CMB data, etc.) Though usually assumed L~, big LA may hide i the eutrio sector. Sice CNB has ot bee detected yet, ow LA may be measured/costraied oly idirectly through its effect o other processes, which have left observable relics or traces i the Uiverse: Dolgov,2002 light elemet abudaces from Big Bag Nucleosythesis Wagoer et al.1967.terasawa&sato, 1988 Serpico&Raffelt, 2005; Pastor, Pito&Raffelt,2009; Simha&Steigma, 2008 Cosmic Microwave Backgroud Lesgourgues&Pastor,1999; Shiraishi et al., 2009; Popa&Vasile, 2008 LSS, etc. Larse&Madse, 1995 iformatio from LA effect o QCD trasitio talk of M. Stuke ; Schwarz&Stuke,09

7 Lepto Asymmetry Effects No-zero LA icreases the radiatio eergy desity 4 2 N eff =15/7(( / ) +2( / ) ) leadig to faster expasio H=(8/3G) 1/2, delayig matter/radiatio equality epoch ifluece BBN, CMB, evolutio of perturbatios i.e. LSS L e > 0.01 effect eutro-proto kietics i pre-bbn epoch ifluece BBN, outcome is L sig depedet Simha&Steigma, 2008: Yp ~ ( ) Neff 0.3 e L 10-7 effects eutrio evolutio, its umber desity, spectrum distributio, oscillatios patter ad hece /p kietics ad BBN DK&Chizhov, 1996, PLB 97, NPB98,2000,2001, DK2010 LA chages the decouplig T of eutrio e p e e p ~ p e e ~

8 Lepto Asymmetry Costraits At preset BBN provides the most striget costrait o L i case of combied variatio of chemical poteials Hase et al., e , I case of eutrio oscillatios degeeracies equilibrate due to oscillatios before BBN Dolgov et al., NPB, 2002 Serpico&Raffelt, Serpico, Pito&Raffelt 13 role : e 2.3 L 5 Simha&Steigma, JCAP, 2008 : e 4 L 7.6 : e 0.1 L ~ Practically stadard H, N~0.03 i the last case (udetectable). However, large ad opposite i two flavours are allowed eff L() ~1 detectable by BBN,CMB Pastor,Pito&Raffelt, 2009 CMB ad LSS provide much looser bouds eff L() modifies the power spectra of radiatio ad matter Lesgourgues&Pastor, 99 CMB (WMAP5+all) ad LSS: 0.7 L 0.6_(2 ) Popa&Vasile, 2008 forcast for Plack: 0.3 Sihiraishi et al.,09 WMAP5+Y(BBN) Christel Smith talk , e, 1.67

9 Asymmetry - Oscillatios Iterplay Lepto Asymmetry Geeratio Oscillatios i a medium are capable to suppress pre-existig asymmetry Barbieri&Dolgov,90.91; Eqvist et al.,1992 Asymmetry is capable to suppress oscillatios Foot&Volkas, 95; DK&Chizhov, NPB 98 LA ca ehace eutrio oscillatios DK&Chizhov, NPB 98 LA may be geerated by MSW resoat eutrio oscillatios i the early Uiverse i active sterile oscillatios There are differet mechaisms producig large LA. LA geeratio possibility i MSW resoat eutrio oscillatios i the early Uiverse i active sterile oscillatios was first foud m 2 >10-5 ev 2 i collisios domiated oscillatios Foot&Volkas 96 m 2 <10-7 ev 2 i the collisioless case DK&Chizhov, L-T=M m( m,, L, T,..) -L-T=M

10 We studied the iterplay betwee small LA ad eutrio oscillatios i the early Uiverse ad their effect o BBN i more detail for the specific case: Neutrio electro-sterile oscillatios 1 = e cos + s si 2 = - e si + s cos effective after active eutrio decouplig m si ev 2 were discussed. Two differet cases of LA were studied: iitially preset ad dyamically geerated by oscillatios. LA effect i desity ad direct effect i -p kietics egligible Eve for fast oscillatio case <p> approximatio ot suitable, LA growth overestimated. Approximate solutios of L(t) were developed. Foot&Volkas 97, Bell,Volkas&Wag,99 I case of late oscillatios strog distortio of eutrio spectrum due to oscillatios. Neutrio mometum distributio should be take ito accout. DK&Chizhov, NPB 96, 98, 2001 DK2010

11 Neutrio oscillatios durig BBN Active-sterile oscillatios may have cosiderable cosmological ifluece! Dyamical effect: Excite additioal light particles ito equilibrium ~g eff T 4 H ~ g GT Fast a s effective before a decouplig - effect CMB through icreasig ad BBN by icreasig H He-4 mass fractio is a strog fuctio of the effective umber of light stable particles at BBN epoch Y d ~0.013 N s (the best speedometer). eff 2 7 geff Ns Ns N 3 4 Distort the eutrio eergy spectrum from the equilibrium FD form chage eutrio-atieutrio asymmetry of the medium (suppress / ehace) Г 2 2 ~ E N F G Effect both expasio rate ad the weak iteractios rates, may distort e eergy spectrum, causig e depletio, eutrio-atieutrio asymmetry geeratio ad iflueces the eutrio ivolved processes i Uiverse, like BBN Kietics, CMB, etc. Active-sterile oscillatios may play crucial role for eutrio ivolved processes i the Uiverse durig BBN, CMB, LSS, CNB He-4 depeds also o the e characteristics e decrease /p freezes earlier 4 Не is overproduced N s Dolgov 81. DK 88, Barbieri, Dolgov 90, Kaiulaie 91, Eqvist et al.,92, Foot&Volkas 95,96; DK&Chizhov 96,97,2000; Dolgov&Villate 03; DK04,07

12 Evolutio of eutrio i presece of е s oscillatios ad LA We followed the evolutio of the oscillatig ad s, accoutig simultaeously for Uiverse expasio, eutrio oscillatios ad eutrio forward scatterig. I case of oscillatios after eutrio decouplig the last term is egligible. ( t) ( t) Q Hp i 0 t i G L N t O G 2 t p MW 2 H, ( ) 2, ( ) F F ( t) ( t) Q Hp i 0 t i G L N t O G 2 t p MW U U, U l e, s H 0 * ie je i il l is free eutrio Hamiltoia Q E T L L L L L d p N 3 ~ ~ 2 ~ LL LL / e 2 H, ( ) 2, ( ) F F e 1 0 i eq i eq LL exp ( E ) / T 1 exp ( E ) / T 0 Ns No-zero LA term leads to coupled itegro-differetial equatios ad hard umerical task. LA term leads to differet evolutio of eutrio ad atieutrio. 7 geff Ns Ns N 3 4

13 Small L<<0.01, that do ot effect directly BBN kietics, ifluece idirectly BBN via oscillatios by: chagig eutrio umber desities chagig eutrio distributio ad spectrum distortio chagig eutrio oscillatios patter (suppressig or ehacig them) Active-sterile oscillatios proceedig after decouplig may strogly distort eutrio eergy spectrum. DK,IJMPD,2004, 2007 Precise descriptio of eutrio mometa distributio is eeded, which further complicates the umerical task. Therefore, this parameter space was ot explored i other studies. I the aalysis 1000 bis are used to describe it i o-resoat case, ad up to 5000 i the resoat case.

14 Oscillatios geerated lepto asymmetry I the regio m 2 si 4 2 <10-7 ev 2 evolutio of LA is domiated by oscillatios ad typically LA has rapid oscillatory behavior. The regio of parameter space for which large geeratio of LA is possible: m si 2 10 ev Geeratio of LA up to 5 times larger tha is foud possible, i.е. L10-5 The aalytical approximatio is i agreemet with bouds existig i literature. Distributio of the eutrio mometa was foud to play extremely importat role for the correct determiatio of LA evolutio. L(t) L(t) I some cases icreasig the resolutio of mometum space leads to chages of oscillatory character ad dimiishes LA. Further aalysis is required to decide if the oscillatory behavior ad LA strog growth is iduced by umerical error. This observatio is i accordace with the studies of other authors i other parameter regios. Bari&Foot,2000 Usually geerated lepto umber oscillates ad chages sig, as illustrated i the figure. It presets the evolutio of LA for m 2 ~ ev 2 ad si 2 10

15 Simultaeous calculatio of evolutio of ucleos i the presece of е s ) ( ) ( ),, ( 2 LL p e p p A e p e d p Hp t ) ( ) ~ ( ) ~,, ( 2 LL p e p A e p e d m ev all mixig agles N s MeV T MeV Oscillatios dyamical ad kietic effect o BBN were foud possible. Y ~0.013 N N= N k,0 - N k,0 N s +N s I BBN with e s ad LA eutrio spectrum distortio ad the desity of electro eutrio may cosiderably differ from the stadard BBN oe, leadig to differet ucleo kietics, ad modified BBN elemet productio. Dyamical asymmetry ad BBN

16 The eutro-to-ucleos freezig ratio X (ad correspodigly the primordially produced He-4) decreases at small mixig parameters values due to asymmetry growth. Dyamical asymmetry ad BBN Nucleos evolutio i the pre-bbn period i the presece of е s was umerically aalyzed for differet sets of oscillatio parameters ad the primordially produced He-4 was umerically calculated. The figure (l.h.s.) shows eutro-to-ucleos freezig ratio depedece for two differet mass differeces o the mixig i case of the accout of asymmetry growth (red curves) ad i case without asymmetry growth accout. DK, 2010 The figure shows eutro-to-ucleos freezig ratio evolutio i the case of asymmetry growth (solid lie) ad i case asymmetry growth eglected (dotted lie).

17 BBN costraits o eutrio oscillatio parameters He-4 is the preferred elemet: abudatly produced (25% by mass), precisely measured (<3 % ucertaity) Y p =0, (stat) 0,005(syst) Izotov&Thua, Sp of 86 low Z HII precisely calculated (0.1% ucertaity) Y p =0,2482 0,0007 has a simple post-bbn chemical evolutio best speedometer ad leptometer sesitive to eutrio characteristics (, N, sp,la ) BBN costraits correspodig to Y p /Y p =3% i case proper accout for spectrum distortio ad asymmetry growth due to oscillatios were obtaied m si ev m m ev large, m 0 DK, Chizhov NPB2000,2001; DK&Paayotova JCAP 2006;DK IJMPD 07

18 Effects of eutrio-atieutrio asymmetry ad distortio of spectrum LA chages eergy spectrum distributio ad the umber desities of е from stadard BBN case. This iflueces the kietics of ucleos durig BBN ad chages the produced light elemet abudaces. The accout of the eutrio-atieutrio asymmetry growth caused by resoat oscillatios leads to relaxatio of the BBN costraits for small mixigs. N s =0 The spectrum distortio leads to a decrease of the weak rates, to a icrease of the /p freezig T ad He overproductio. Correspodigly the accout of spectrum distortio leads to stregtheig of BBN costraits at large mixigs.

19 BBN costraits o eutrio oscillatio parameters Costrait cotours, correspodig to 3 ad 5% Helium-4 overproductio. Y p /Y p =5.2% A order of magitude better i mass differeces tha the existig cosmological costraits due to the exact accout of spectrum distributio distortio Y p /Y p =3% More precisely costraiig the mixig agle thaks to the correct accout of asymmetry growth ad spectrum distortio DK,Paayotova, 2006 ; DK, 2007 The dotted blue (red) cotour presets Y p /Y p =3% (Y p /Y p =5.2% ) for N s =0, the solid blue (red) cotour presets Y p /Y p =3% (Y p /Y p =5%) for N s =0,5. Excluded 2 of the possible solutios of the solar eutrio problem LMA (large mixig agle solutio) ad LOW (low mixig agle solutio) (1996, 1999) Excludes electro-sterile solutio to LSND Additioal s populatio ad additioal LA may stregthe or relax BBN costraits o oscillatios.

20 Iitial asymmetry, oscillatios ad BBN The umerical aalysis of BBN for the etire rage of mixig parameters of the model ad with iitial small LA has proved that L >10-7 may cosiderably ifluece BBN: smaller asymmetries may be safely eglected (which reduces eormously the computatioal time), L ~10-7 ehaces oscillatios, while as L ( m ) 2 2/3 ihibit oscillatios. L 0.1( m ) Small 10-7 <L<<0.01, ot effectig directly BBN kietics, ifluece idirectly BBN via oscillatios. 2 2/3 suppresses oscillatios, ad asymmetries as big Y m 2,, L p He-4 productio depedece o oscillatio parameters ad o LA shows that, i case of eutrio oscillatios: BBN ca feel extremely small L: dow to 10-7 Large eough L chage primordial productio of He by ehacig or suppressig oscillatios. BBN with oscillatios is the best kow leptometer.

21 LA bigger tha 10-5 leads to a total suppressio of oscillatios effect o BBN ad hece, elimiates the BBN bouds o oscillatio parameters. I that case, istead, the followig approximate boud holds: m L 2 3/ 2 2 si 2 1 si lgl=-10 si lgl=-6 lgl=-5 lgl logm 2 The depedeces of helium productio o the iitial LA for differet mixigs (to the left) ad o mass differeces for three differet values of LA.

22 Chage of BBN costraits by LA Lepto asymmetry may relax BBN costraits at large mixigs ad stregthe them at small mixig. The figure presets the chage of the BBN costraits i case of L=10-6. Isohelium cotours are calculated for the case with lepto asymmetry (i colors), ad for the case of lepto asymmetry of the order of the baryo oe (dashed lies). Large eougth LA may alleviate BBN oscillatios costraits L ( m ) 2 2/3

23 Summary We have foud effective lepto asymmetry geeratio mechaism i active-sterile Mikheyev- Smirov-Wolfestei oscillatios, effective after eutrio decouplig. Higher resolutio for the descriptio of the eutrio mometa distributio is required for the ivestigatio of the asymmetry behavior i this oscillatio parameter regio. The istability regio i the oscillatio parameter space, where cosiderable growth of LA takes place, was determied umerically for the case of o-equilibrium eutrio oscillatios. We provided a detail umerical aalysis of the iterplay betwee small lepto asymmetry LA << 0.01, either relic (iitially preset) or dyamical (geerated by MSW active-sterile eutrio oscillatios) ad eutrio oscillatios for the case of active-sterile oscillatios occurrig after electro eutrio decouplig. The evolutio of asymmetry growth i case of small mass differeces ad relatively big mixig agles was studied i more detail. The parameter rage for which lepto asymmetry is able to ehace, suppress or ihibit oscillatios is determied. Cosmological ifluece of such small lepto asymmetries, which do ot have direct effect o ucleos kietics durig BBN, is discussed ad show ot to be egligible. Such small asymmetries are ivisible by CMB, but may be felt by BBN: lepto asymmetries as small as 10-7 may be felt by BBN i case of eutrio oscillatios. The effect of the dyamically geerated ad iitially preset LA o BBN with oscillatios was studied. Relic LA preset durig BBN, depedig o its value, ca stregthe, relax or wave out BBN costraits o oscillatios. It relaxes BBN bouds at large mixig ad stregthes them at small mixigs. Large eough LA alleviates BBN costraits o oscillatio parameters. Dyamically geerated asymmetry relaxes BBN costraits at small mixig agles.

24 Active-sterile oscillatios may cosiderably distort eutrio spectrum ad produce eutrio-atieutrio asymmetry, thus ifluecig BBN. BBN is the most sesitive cosmological probe of umber of eutrio species, of distortios i the eergy distributio of eutrios, lepto asymmetry, eutrio mass differeces ad mixigs, etc. It provides costraits o may eutrio characteristics. Не-4 primordial productio depeds strogly o the expasio rate ad o the lepto asymmetry of the Uiverse - it is the best speedometer ad leptometer. BBN costraits o eutrio oscillatios parameters deped lepto asymmetry i the Uiverse. otrivially o the

25 Благодаря за вниманието! Thaks for the attetio!