Rosario Gianluca Pizzone INFN LNS Catania Italy

Transcription

1 Primordial Nucleosynthesis revisited via Trojan Horse results Rosario Gianluca Pizzone INFN LNS Catania Italy

2 Primordial nucleosynthesis is one of the pillars of the current Cosmological models. Main evidences of Standard Big Bang scenario (also from this week): Galactic expansion (Hubble Law) from SN measurements, Cosmic Microwave Background radiation probes the universe at time around 3x10 5 years after BB Primordial nucleosynthesis probes the universe at around 1-20 minutes after Big Bang!! The only in the radiation dominated era

3 BBN network and observed isotopes 12 relevant reactions were Selected whose importance Is connected with formation And destruction of the primordial isotopes. 4 of them were studied by THM (marked in red) Primordial Isotopes: H and D 3 He and 4 He 7 Li (partially) By studying the abundances of those isotopes and Retrieving their primordial abundance one can get Hints on BBN and the baryon to photon ratio, thus Testing the Big Bang Model.

4 Comparison of observed primordial abundances with calculated ones as a function of the baryon-to-photon ratio From abundances to cosmological parameters and viceversa

5 Observational status for Li LiBeB: A(X).vs.[Fe/H] Different features can be extracted by studying the abundance.vs.metallicity scatter plot: ifferent features can be extracted by tudying the abundance.vs.metallicity catter plot: ) 1)at it is evident lower that metallicity, the number lithium of abundances observations exhibit for the lithium so-called are Liplateau (Spite & Spite A&A, 1982) large Primordial compared Nucleosynthesis; with those of beryllium and, more evident, with boron$ 10 Region of Abs. Lines; (Fields et al., ApJ, 2005) ) at lower metallicity, lithium abundances exhibit the so-called Li-plateau (Spite & Spite A&A, (Cyburt et al., PLB, 2005) 1982)$Primordial Nucleosynthesis; ) beryllium and boron abundances are strongly related with metallicity, thus suggesting their production mainly via a synthesis occurring in a continuosly evolved ISM$GCR s nucleosynthesis; Primordial Lithium (Li/H) Observed 1-2*10- Primordial Lithium (Li/H)WMAP 4.3* WMAP [Fe/H]

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7 8 Pettini and Cooke For the other baryometers D from QSO absorbers, damped Lyman alpha systems line suffers very little contaminat ion by gas unrelat ed to t he DLA, easing the det ermination of N (H i); (ii) eight D i Lyman lines of widely differing f -values are accessible; (iii) t he kinematic struct ure of t he gas is simple, wit h only 2 3 components cont ribut ing t o t he absorption lines; and (iv) t he spect rum analysed is of moderat ely high S/ N. We t herefore consider it wort hwhile t o examine t he cosmological implications of the new measurement reported here before discussing t he full sample of available D/ H measures at high redshift. WMAP In t he following, value we t ake: 2.55 x10-5 Obs (Pettini et al 2012) (D i/ H i) DLA =(D/ H) DLA =(D/ H) p. (4) Theassumptions underlying these equalities are that: (i) t he fract ional ionizat ions of H and D are t he same, (ii) D is not depleted relative to H, and (iii) t he destruct ion of D through astrat ion prior to the t ime when we observe the DLA has been negligible. Concerning t he first assumpt ion, we are not aware of a physical process t hat would under- or over-ionise 4 He in metal poor HII one isot ope relat ive to the ot her. Dust depletion of D in local interstellar medium has been proposed to explain theregions surprising range of D/ H values found along different sightlines in our Galaxy (Linsky et al. 2006), but is unlikely to be important in metal- and dust-poor DLAs where even highly refract ory element s are present in near-solar relat ive proport ions (A kerman et al. 2005; V ladilo et al. 2006; Ellison WMAP value Obs (Izotov et al.) et al. 2007). Given the low met allicity of the z abs = DLA, where N, O, Si, and Fe have abundances less than 1/ 100 of solar (Cooke et al. 2011), the t hird assumpt ion is supported by chemical evolut ion models which ent ert ain littlereduction of t he D abundance from its primordial value when such a small fract ion of t he gas has evidently been cycled t hrough st ars (Romano et al. 2006). Recent ly, St eigman (privat e communicat ion) has updat ed t he relat ions between (D/ H) p and Ω b,0 h 2 given by Simha & St eigman (2008) and St eigman (2007), as follows: Pettini et al Pettini et al Figure 7. Measures of the deut erium abundance in high redshift QSO absorbers. Only cases were t he deut erium absorpt ion is clearly resolved from nearby spect ral features are shown (see text ). T he red star refers Izotov thet newal. measurement 2007 reported here, with errors smaller t han t he symbol size. The horizont al lines are drawn at t he weight ed mean value of log (D/ H) and its error, as det ermined wit h t he boot st rap met hod. T he yellow shaded area shows t he range in Ω b,0 h 2 (CMB) from K eisler et al. (2011). Recent ly, K eisler et al. (2011) combined their measurement of t he CMB angular power spectrum from t he South Pole Telescope (SPT ) wit h thepower spect ra from t he sevenyear Wilkinson Microwave Anisot ropy Probe (WMAP) dat a release to better const rain cosmological paramet ers. From this analysis, it was concluded: 100Ω b,0 h 2 (CMB) = 2.22 ± (10) (see Table 3 of K eisler et al. 2011). The agreement bet ween eqs. (9) and (10) is very encouraging. If t he value of (D/ H) p we have deduced here is

8 (p, ) He reaction was extensively studied in the last 20 years both directly [90, 105] and indi THM. The Role of nuclear cross sections st recent dat a-set for the S-factor for the reaction 7 Li(p, ) 4 He obtained with the Trojan Hors e breakup Reaction are shown rate indetermination Figure 4 [46]. The by curve means is aof function the formula fit to the dat a (bot h THM d ergies (Rolfs above & 0.4Rodney, MeV) using 1988) Eq. (4). The fit parameters are listed in the third column of xpression is then used to calculate the reaction rate following equation II, as for the other ex æ N A < s v >= 8 ö ç èpm ø 1/2 N A kt ò S ( ) 3/2 b (E)e -2ph- 0 E kt de E. Reaction r at es wit h TH dat a Thus the bare astrophysical S(E) factor must be known in the whole astrophysical range and then integrated numerically. It can be expressed as a function of T 9 as: ction rates for the the four THM reactions mentioned above have been calculated introducin in Eq. (II). The numerical results are then fitted with the expression N A hσvi =exp a 1 + a 2 lnt 9 + a 3 + a 4 T 1/ a 5 T 1/ a 6 T 2/ a 7 T 9 + a 8 T 4/ a 9 T 5/ 3 9 T 9 rporates the relevant temperature dependence of the reaction rates during the BBN. The (d,p) With 3 H and a i the parameters 2 H(d,n) 3 He reactions which are can given be for bot fitted h the THM and measurements then used as for well as next Astrophysics section for details) in table IV. The coefficients for the 3 He(d,p) 4 He and 7 Li(p, ) 4 He

9 Why TH measurements? The direct measurements at low-energies have been performed and discussed by several groups in last 50 years. Several reliable data sets are available but Only extrapolations have been performed in correspondence of the energy window relevant for astrophysics in many cases (even if low energy experimental data are available extrapolations are required due to the presence of electron screening, Assenbaum 1987); Thus, the indirect THM approach has been adopted to measure the bare nucleus S(E)-factor

10 The 7 Li(p,α) 4 He reaction rate For the rate both direct And THM data were taken into account Red: THM Data Blue: Direct Data - Azure R-Matrix fit Extensive efforts for THM: Spitaleri et al.1999, Lattuada et al. APJ 2001, RGP et al A&A 2003, Lamia et al., A&A 2012 PRELIMINARY RESULTS for the reaction rate 10

11 The updated d(d,n) 3 He reaction rate Red: Direct Data Blue: THM Data - Azure R-Matrix fit Extensive efforts for THM: Tumino et al 2011, Pizzone et al 2013 For the rate both direct And THM data were taken into account PRELIMINARY RESULTS for the reaction rate 11

12 The updated d(d,p) 3 H reaction rate Red: Direct Data Blue: THM Data - Azure R-Matrix fit Extensive efforts for THM: Tumino et al 2011, Pizzone et al 2013 For the rate both direct And THM data were taken into account PRELIMINARY RESULTS for the reaction rate

13 The updated 3 He(d,p) 4 He reaction rate Red: THM Data Blue: Direct Data - Azure R-Matrix fit Extensive efforts for THM: La Cognata et al For the rate both direct And THM data were taken into account Future applications to 6 Li(p,a) 3 He & 6 Li(d,a) 4 He??? Currently under investigation

14 Applications to primordial Nucleosynthesis SKM code Figure 7: Calculated BBN abundance of 3,4 He, D and 7 Li as a function of time and temperature. Black line represents 4 He mass fraction, green the deuterium abundance, red the 3 He abundance and blue the 7 Li abundance. T he band error represents Inputs. the uncertainty in the T HM measurements and their influence on the abundances. The 7 Li(p,a) 4 He reaction THM rate Was adopted as a physical input for the BBN model (Kawano 1988), in collaboration with Carlos Bertulani togheter with d(d,p)t & d(d,n) 3 He reaction rates The results are in agreement with Observations (except 7 Li) and with results obtained using direct nuclear [24, 25]). The 3 He abundances are adopted from Ref. [27] as a lower bound to the primordial abundance. The lithium abundance arises from observat ions of star which provide a sample of the lithium plat eau [28]. In figure 7 it is reported the calculat ed abundance for 3,4 He, D and 7 Li as a function of time and temperat ure for the BBN. The band represent s t he uncert ainty derived from T HM measurement s for each element. T he overall behavior is similar to ot her studies (see for example [1]) as it is also clear from table VI. Figure 7: Calculated BBN abundance of 3,4 He, D and 7 Li as a function of time and temperature. Black line represents 4 He mass fraction, green the deuterium abundance, red the 3 He abundance and blue the 7 Li abundance. The band error represents the uncertainty in the THM measurements and their influence on the abundances. Table VI: BBN predictions using di erent set of data (see text) compared with observations. (a) T he mass fraction for 4 He, Y p =0.2565± (0.001 statistical and systematic), is from Ref. [26]. (b) The mean deuterium abundance is the mean average h(d/ H)i = (2.82 ± 0.26) 10 5,which is equivalent to b h 2 (BBN) = ± [22]. (c) T he 3 He abundances are adopted from Ref. [27] as a lower bound to the primordial abundance. (d) The lithium abundance arises from observations of star which provide a sample of the lithium plateau [28]. Yields Direct data T H d(d,p)t TH d(d,n) 3 He TH 3 He(d,p) TH 7 Li(p, ) 4 He TH all Observation [24, 25]). Y The 3 p He abundances are adopted from Ref. [27] as a lower bound to the primordial abundance. The lithium a) ± 0.006( abundance D/ H ( 10 5 ) arises from2.621 observat ions of 0.036star2.645 which provide a sample of the lithium plat eau [28]. In figure 7 it is reported the calculat ed abundance for 3, He, D and ± 0.26 ( b) 3 He/ H ( 10 6 ) Li as a function of time 11. ± and 2. ( c) temperat ure for the BBN. The band 7 Li/ H represent ( ) s4.460 t he uncertainty derived from T HM measurement s for each element. T he overall behavior is similar ± 0.31 ( d) to ot her studies (see for example [1]) as it is also clear from table VI.

15 Mount Etna and the Sicilian East Coast as seen from the ISS