Search

We performed a novel $\Sigma^+ p$ scattering experiment at the J-PARC Hadron Experimental Facility. Approximately 2400 $\Sigma^+ p$ elastic scattering events were identified from $4.9 \times 10^7$ tagged $\Sigma^+$ particles in the $\Sigma^+$ momentum range 0.44 -- 0.80 GeV/$c$. The differential cross sections of the $\Sigma^+ p$ elastic scattering were derived with much better precision than in previous experiments. The obtained differential cross sections were approximately 2 mb/sr or less, which were not as large as those predicted by the fss2 and FSS models based on the quark cluster model in the short-range region. By performing phase-shift analyses for the obtained differential cross sections, we experimentally derived the phase shifts of the $^3 S_1$ and $^1 P_1$ channels for the first time. The phase shift of the $^3 S_1$ channel, where a large repulsive core was predicted owing to the Pauli effect between quarks, was evaluated as $20^\circ<|\delta_{^3S_1}|<35^\circ$. If the sign of $\delta_{^3S_1}$ is assumed to be negative, the interaction in this channel is moderately repulsive, as the Nijmegen extended-sort-core models predicted.

The differential cross sections of the {\Sigma}-p --> {\Lambda} n reaction were measured accurately for the {\Sigma}- momentum (p_{{\Sigma}}) ranging from 470 to 650 MeV/c at the J-PARC Hadron Experimental Facility. Precise angular information about the {\Sigma}-p --> {\Lambda} n reaction was obtained for the first time by detecting approximately 100 reaction events at each angular step of {\Delta}cos{\theta} = 0.1. The obtained differential cross sections show slightly forward-peaking structure in the measured momentum regions.The cross sections integrated for -0.7 < cos{\theta} < 1.0 were obtained as 22.5 +- 0.68 (stat.) +- 0.65 (syst.) mb and 15.8 +-0.83(stat.) +- 0.52 (syst.) mb for 470

In this study, we developed a new proton detector system called CATCH, which was designed for a scattering experiment involving a $\Sigma$ hyperon and a proton (J-PARC E40). CATCH is a cylindrical detector system covering an inner target that can be used to measure the trajectory and energy of a proton emitted from the target for the kinematic identification of a $\Sigma$p scattering event. It comprises a cylindrical fiber tracker (CFT), a bismuth germanate (BGO) calorimeter, and a plastic scintillator hodoscope (PiID), which are coaxially arranged from the inner to the outer sides. The CFT is a tracking detector consisting of 5,000 scintillation fibers, and it has two types of cylindrical layers in which the fibers are arranged in straight and spiral configurations. 24 BGO crystals are placed around the CFT to measure the kinetic energy of the recoil proton. The PiID is used to determine whether the recoil proton is stopped in the BGO calorimeter. We performed proton-proton (pp) and proton-carbon (pC) scattering experiments using an 80 MeV proton beam to evaluate the performance of CATCH. The total energy resolution for the recoil proton was 2.8 MeV in $\sigma$ for the entire angular region after the energy calibrations of the BGO calorimeter and the CFT. The angular resolution of the CFT was 1.27 degrees in $\sigma$ for the proton, and the time resolution was more than 1.8 ns in $\sigma$. We also developed an analysis method for deriving the cross section of the pp scattering using CATCH. The obtained relative differential cross section for the pp elastic scattering was consistent with that obtained by reliable partial wave analysis, and the systematic error was maintained at below 10%. These performance results satisfy our requirements for a reliable detection system for the $\Sigma$p scattering experiment conducted at J-PARC .

We report the first (in)elastic scattering measurement of $^{25}\mathrm{Al}+p$ with the capability to select and measure in a broad energy range the proton resonances in $^{26}$Si contributing to the $^{22}$Mg$(\alpha,p)$ reaction at type I x-ray burst energies. We measured spin-parities of four resonances above the $\alpha$ threshold of $^{26}$Si that are found to strongly impact the $^{22}$Mg$(\alpha,p)$ rate. The new rate advances a state-of-the-art model to remarkably reproduce light curves of the GS 1826$-$24 clocked burster with mean deviation $<9$ % and permits us to discover a strong correlation between the He abundance in the accreting envelope of photospheric radius expansion burster and the dominance of $^{22}$Mg$(\alpha,p)$ branch., Comment: accepted by Physical Review Letters on 5 August 2021, published 19 October 2021

A high statistics $\Sigma p$ scattering experiment has been performed at the J-PARC Hadron Experimental Facility. Data for momentum-tagged $\Sigma^{-}$ running in a liquid hydrogen target were accumulated by detecting the $\pi^{-}p \to K^{+}\Sigma^{-}$ reaction with a high intensity $\pi^{-}$ beam of 20 M/spill. Differential cross sections of the $\Sigma^{-}p$ elastic scattering were derived with a drastically improved accuracy by identifying the largest statistics of about 4,500 events from 1.72 $\times$ $10^{7}$ $\Sigma^{-}$. The derived differential cross section shows a clear forward-peaking angular distribution for a $\Sigma^{-}$ momentum range from 470 to 850 MeV/$c$. The accurate data will impose a strong constraint on the theoretical models of the baryon-baryon interactions.

Bound-systems of $\Xi^-$--$^{14}_{}{\rm N}$ are studied via $\Xi^-$ capture at rest followed by emission of a twin single-$\Lambda$ hypernucleus in the emulsion detectors. Two events forming extremely deep $\Xi^-$ bound states were obtained by analysis of a hybrid method in the E07 experiment at J-PARC and reanalysis of the E373 experiment at KEK-PS. The decay mode of one event was assigned as $\Xi^-+^{14}_{}{\rm N}\to^{5}_{\Lambda}{\rm He}$+$^{5}_{\Lambda}{\rm He}$+$^{4}_{}{\rm He}$+n. Since there are no excited states for daughter particles, the binding energy of the $\Xi^-$ hyperon, $B_{\Xi^-}$, in $^{14}_{}{\rm N}$ nucleus was uniquely determined to be 6.27 $\pm$ 0.27 MeV. Another $\Xi^-$--$^{14}_{}{\rm N}$ system via the decay $^{9}_{\Lambda}{\rm Be}$ + $^{5}_{\Lambda}{\rm He}$ + n brings a $B_{\Xi^-}$ value, 8.00 $\pm$ 0.77 MeV or 4.96 $\pm$ 0.77 MeV, where the two possible values of $B_{\Xi^-}$ correspond to the ground and the excited states of the daughter $^{9}_{\Lambda}{\rm Be}$ nucleus, respectively. Because the $B_{\Xi^-}$ values are larger than those of the previously reported events (KISO and IBUKI), which are both interpreted as the nuclear $1p$ state of the $\Xi^-$--$^{14}_{}{\rm N}$ system, these new events give the first indication of the nuclear $1s$ state of the $\Xi$ hypernucleus, $^{15}_{\Xi}{\rm C}$., Comment: 26 pages, 7 figures

In an emulsion-counter hybrid experiment performed at J-PARC, a $\Xi^-$ absorption event was observed which decayed into twin single-$\Lambda$ hypernuclei. Kinematic calculations enabled a unique identification of the reaction process as $\Xi^{-} + ^{14}$N$\ \rightarrow\ ^{10}_\Lambda$Be + $^5_\Lambda$He. For the binding energy of the $\Xi^{-}$ hyperon in the $\Xi^-$-$^{14}$N system a value of $1.27 \pm 0.21$ MeV was deduced. The energy level of $\Xi^-$ is likely a nuclear $1p$ state which indicates a weak ${\Xi}N$-$\Lambda\Lambda$ coupling.

A double-$\Lambda$ hypernucleus, ${}_{\Lambda\Lambda}\mathrm{Be}$, was observed by the J-PARC E07 collaboration in nuclear emulsions tagged by the $(K^{-},K^{+})$ reaction. This event was interpreted as a production and decay of $ {}_{\Lambda\Lambda}^{\;10}\mathrm{Be}$, ${}_{\Lambda\Lambda}^{\;11}\mathrm{Be}$, or ${}_{\Lambda\Lambda}^{\;12}\mathrm{Be}^{*}$ via $\Xi^{-}$ capture in ${}^{16}\mathrm{O}$. By assuming the capture in the atomic 3D state, the binding energy of two $\Lambda$ hyperons$\,$($B_{\Lambda\Lambda}$) of these double-$\Lambda$ hypernuclei are obtained to be $15.05 \pm 0.11\,\mathrm{MeV}$, $19.07 \pm 0.11\,\mathrm{MeV}$, and $13.68 \pm 0.11\,\mathrm{MeV}$, respectively. Based on the kinematic fitting, ${}_{\Lambda\Lambda}^{\;11}\mathrm{Be}$ is the most likely explanation for the observed event., Comment: 11 pages, 3 figures

The goal of this reply is to draw attention of the readers that the major problems rose in the short Comment authored by A.M. Mukhamedzhanov, X. Tang and D.Y. Pang (arXiv:1806.05921) are totally groundless., Comment: 4 pages, 2 figures

We report on the first observation of $\gamma$ rays emitted from an $sd$-shell hypernucleus, $\rm ^{19}_{\Lambda}F$. The energy spacing between the ground state doublet, $1/2^{+}$ and $3/2^{+}$ states, of $\rm ^{19}_{\Lambda}F$ is determined to be $\rm 315.5 \pm 0.4 (stat) ^{+0.6}_{-0.5} (syst)~keV$ by measuring the $\gamma$-ray energy from the $M1(3/2^{+} \rightarrow 1/2^{+})$ transition. In addition, three $\gamma$-ray peaks were observed and assigned as $E2(5/2^{+} \rightarrow 1/2^{+})$, $E1(1/2^{-} \rightarrow 1/2^{+})$, and $E1(1/2^{-} \rightarrow 3/2^{+})$ transitions. The excitation energies of the $5/2^{+}$ and $1/2^{-}$ states are determined to be $\rm 895.2 \pm 0.3 (stat) \pm 0.5 (syst)~keV$ and $\rm 1265.6 \pm 1.2 (stat) ^{+0.7}_{-0.5} (syst)~keV$, respectively. It is found that the ground state doublet spacing is well described by theoretical models based on existing $s$- and $p$-shell hypernuclear data.

We searched for the bound state of the neutron-rich $\Lambda$-hypernucleus ${}^{6}_{\Lambda}$H, using the ${}^{6}$Li($\pi^{-}, K^{+}$)X double charge-exchange reaction at a $\pi^{-}$ beam momentum of 1.2 GeV/c at J-PARC. A total of $1.4 \times 10^{12}$ $\pi^{-}$ was driven onto a ${}^{6}$Li target of 3.5-g/$\rm cm^2$ thickness. No event was observed below the bound threshold, i.e., the mass of ${}^{4}_{\Lambda}$H + 2n, in the missing-mass spectrum of the ${}^{6}$Li($\pi^{-}, K^{+}$)X reaction in the $2^{\circ}$ < $\theta_{\pi K}$ < $20^{\circ}$ angular range. Furthermore, no event was found up to 2.8 MeV/$c^2$ above the bound threshold. We obtained the the double-differential cross section spectra of the ${}^{6}$Li($\pi^{-}, K^{+}$)X reaction in the angular range of $2^{\circ}$ < $\theta_{\pi K}$ < $14^{\circ}$. An upper limit of 0.56 nb/sr (90% C.L.) was obtained for the production cross section of the ${}^{6}_{\Lambda}$H hypernucleus bound state. In addition, not only the bound state region, but also the $\Lambda$ continuum region and part of the $\Sigma^{-}$ quasi-free production region of the ${}^{6}$Li($\pi^{-}, K^{+}$)X reaction, were obtained with high statistics. The present missing-mass spectrum will facilitate the investigation of the $\Sigma^{-}$-nucleus optical potential for $\Sigma^{-}$-${}^{5}$He through spectrum shape analysis., Comment: 24 pages, 17 figures

Background: Type I x-ray bursts are the most frequent thermonuclear explosions in the galaxy, resulting from thermonuclear runaway on the surface of an accreting neutron star. The $^{30}$S($\alpha$,p) reaction plays a critical role in burst models, yet insufficient experimental information is available to calculate a reliable, precise rate for this reaction. Purpose: Our measurement was conducted to search for states in $^{34}$Ar and determine their quantum properties. In particular, natural-parity states with large $\alpha$-decay partial widths should dominate the stellar reaction rate. Method: We performed the first measurement of $^{30}$S+$\alpha$ resonant elastic scattering up to a center-of-mass energy of 5.5 MeV using a radioactive ion beam. The experiment utilized a thick gaseous active target system and silicon detector array in inverse kinematics. Results: We obtained an excitation function for $^{30}$S($\alpha$,$\alpha$) near $150^{\circ}$ in the center-of-mass frame. The experimental data were analyzed with an $R$-Matrix calculation, and we observed three new resonant patterns between 11.1 and 12.1 MeV, extracting their properties of resonance energy, widths, spin, and parity. Conclusions: We calculated the resonant thermonuclear reaction rate of $^{30}$S($\alpha$,p) based on all available experimental data of $^{34}$Ar and found an upper limit about one order of magnitude larger than a rate determined using a statistical model. The astrophysical impact of these two rates has been investigated through one-zone postprocessing type I x-ray burst calculations. We find that our new upper limit for the $^{30}$S($\alpha$,p)$^{33}$Cl rate significantly affects the predicted nuclear energy generation rate during the burst., Comment: 16 pages, 12 figures

It is a well-known fact that a cluster of nucleons can be formed in the interior of an atomic nucleus, and such clusters may occupy molecular-like orbitals, showing characteristics similar to normal molecules consisting of atoms. Chemical molecules having a linear alignment are commonly seen in nature, such as carbon dioxide. A similar linear alignment of the nuclear clusters, referred to as linear-chain cluster state (LCCS), has been studied since the 1950s, however, up to now there is no clear experimental evidence demonstrating the existence of such a state. Recently, it was proposed that an excess of neutrons may offer just such a stabilizing mechanism, revitalizing interest in the nuclear LCCS, specifically with predictions for their emergence in neutron-rich carbon isotopes. Here we present the experimental observation of {\alpha}-cluster states in the radioactive 14C nucleus. Using the 10Be+{\alpha} resonant scattering method with a radioactive beam, we observed a series of levels which completely agree with theoretically predicted levels having an explicit linear-chain cluster configuration. We regard this as the first strong indication of the linear-chain clustered nucleus., Comment: 15 pages, 3 figures

The $^{11}$C($\alpha$, p) reaction is an important $\alpha$-induced reaction competing with $\beta$-limited hydrogen-burning processes in high-temperature explosive stars. We directly measured its reaction cross sections both for the ground-state transition ($\alpha$, $p_{0}$) and the excited-state transitions ($\alpha$, $p_{1}$) and ($\alpha$, $p_{2}$) at relevant stellar energies 1.3 - 4.5 MeV by an extended thick-target method featuring time of flight for the first time. We revised the reaction rate by numerical integration including the ($\alpha$, $p_{1}$) and ($\alpha$, $p_{2}$) contributions and also low-lying resonances of ($\alpha$, $p_{0}$) using both the present and the previous experimental data which were totally neglected in the previous compilation works. The present total reaction rate lies between the previous ($\alpha$, $p_{0}$) rate and the total rate of the Hauser-Feshbach statistical model calculation, which is consistent with the relevant explosive hydrogen-burning scenarios such as the $\nu p$-process., Comment: 8 pages, 8 figures, final version as submitted to Physical Review C for publication after peer-review

The energy spacing between the ground-state spin doublet of $^4_\Lambda $He(1$^+$,0$^+$) was determined to be $1406 \pm 2 \pm 2$ keV, by measuring $\gamma$ rays for the $1^+ \to 0^+$ transition with a high efficiency germanium detector array in coincidence with the $^4$He$(K^-,\pi^-)$ $^4_\Lambda $He reaction at J-PARC. In comparison to the corresponding energy spacing in the mirror hypernucleus $^4_\Lambda $H, the present result clearly indicates the existence of charge symmetry breaking (CSB) in $\Lambda N$ interaction. It is also found that the CSB effect is large in the $0^+$ ground state but is by one order of magnitude smaller in the $1^+$ excited state, demonstrating that the $\Lambda N$ CSB interaction has spin dependence.

Measurement of nuclear cross sections at astrophysical energies involving unstable species is one of the most challenging tasks in experimental nuclear physics. The use of indirect methods is often unavoidable in this scenario. In this paper the Trojan Horse Method is applied for the first time to a radioactive ion beam induced reaction studying the $^{18}$F($p,{\alpha}$)$^{15}$O process at low energies relevant to astrophysics via the three body reaction $^{2}$H($^{18}$F,${\alpha}^{15}$O)n. The knowledge of the $^{18}$F($p, {\alpha}$)$^{15}$O reaction rate is crucial to understand the nova explosion phenomena. The cross section of this reaction is characterized by the presence of several resonances in $^{19}$Ne and possibly interference effects among them. The results reported in Literature are not satisfactory and new investigations of the $^{18}$F($p,{\alpha}$)$^{15}$O reaction cross section will be useful. In the present work the spin-parity assignments of relevant levels have been discussed and the astrophysical S-factor has been extracted considering also interference effects, Comment: 7 pages, 4 figures

The pentaquark $\Theta^+$ has been searched for via the $\pi^-p \to K^-X$ reaction with beam momenta of 1.92 and 2.01 GeV/$c$ at J-PARC. A missing mass resolution of 2 MeV (FWHM) was achieved but no sharp peak structure was observed. The upper limits on the production cross section averaged over the scattering angle from 2$^{\circ}$ to 15$^{\circ}$ in the laboratory frame were found to be less than 0.28 $\mu$b/sr at the 90\% confidence level for both the 1.92- and 2.01-GeV/$c$ data. The systematic uncertainty of the upper limits was controlled within 10\%. Constraints on the $\Theta^+$ decay width were also evaluated with a theoretical calculation using effective Lagrangian. The present result implies that the width should be less than 0.36 and 1.9 MeV for the spin-parity of $1/2^+$ and $1/2^-$, respectively., Comment: 12 pages, 9 figures; published version

The $^{18}$Ne($\alpha$,$p$)$^{21}$Na reaction is thought to be one of the key breakout reactions from the hot CNO cycles to the rp-process in type I x-ray bursts. In this work, the resonant properties of the compound nucleus $^{22}$Mg have been investigated by measuring the resonant elastic scattering of $^{21}$Na+$p$. An 89 MeV $^{21}$Na radioactive beam delivered from the CNS Radioactive Ion Beam Separator bombarded an 8.8 mg/cm$^2$ thick polyethylene (CH$_{2}$)$_{n}$ target. The $^{21}$Na beam intensity was about 2$\times$10$^{5}$ pps, with a purity of about 70% on target. The recoiled protons were measured at the center-of-mass scattering angles of $\theta_{c.m.}$$\approx$175.2${^\circ}$, 152.2${^\circ}$, and 150.5${^\circ}$ by three sets of $\Delta E$-$E$ telescopes, respectively. The excitation function was obtained with the thick-target method over energies $E_x$($^{22}$Mg)=5.5--9.2 MeV. In total, 23 states above the proton-threshold in $^{22}$Mg were observed, and their resonant parameters were determined via an $R$-matrix analysis of the excitation functions. We have made several new $J^{\pi}$ assignments and confirmed some tentative assignments made in previous work. The thermonuclear $^{18}$Ne($\alpha$,$p$)$^{21}$Na rate has been recalculated based on our recommended spin-parity assignments. The astrophysical impact of our new rate has been investigated through one-zone postprocessing x-ray burst calculations. We find that the $^{18}$Ne($\alpha$,$p$)$^{21}$Na rate significantly affects the peak nuclear energy generation rate, reaction fluxes, as well as the onset temperature of this breakout reaction in these astrophysical phenomena.

We have carried out an experiment to search for a neutron-rich hypernucleus, $^6_{\Lambda}$H, by the $^6$Li($\pi^-,K^+$) reaction at $p_{\pi^-}$ =1.2 GeV/$c$. The obtained missing mass spectrum with an estimated energy resolution of 3.2 MeV (FWHM) showed no peak structure corresponding to the $^6_{\Lambda}$H hypernucleus neither below nor above the $^4_{\Lambda}$H$+2n$ particle decay threshold. An upper limit of the production cross section for the bound $^6_{\Lambda}$H hypernucleus was estimated to be 1.2 nb/sr at 90% confidence level., Comment: 6 pages, 5 figures, published version

The $^{18}$Ne($\alpha$,$p$)$^{21}$Na reaction provides a pathway for breakout from the hot CNO cycles to the $rp$-process in type I x-ray bursts. To better determine this astrophysical reaction rate, the resonance parameters of the compound nucleus $^{22}$Mg have been investigated by measuring the resonant elastic scattering of $^{21}$Na+$p$. An 89 MeV $^{21}$Na radioactive ion beam was produced at the CNS Radioactive Ion Beam Separator and bombarded an 8.8 mg/cm$^2$ thick polyethylene target. The recoiled protons were measured at scattering angles of $\theta_{c.m.}$$\approx 175 {^\circ}$ and 152${^\circ}$ by three $\Delta E$-$E$ silicon telescopes. The excitation function was obtained with a thick-target method over energies $E_x$($^{22}$Mg)=5.5--9.2 MeV. The resonance parameters have been determined through an $R$-matrix analysis. For the first time, the $J^{\pi}$ values for ten states above the alpha threshold in $^{22}$Mg have been experimentally determined in a single consistent measurement. We have made three new $J^{\pi}$ assignments and confirmed seven of the ten tentative assignments in the previous work. The $^{18}$Ne($\alpha$,$p$)$^{21}$Na reaction rate has been recalculated, and the astrophysical impact of our new rate has been investigated through one-zone postprocessing x-ray burst calculations. We find that the $^{18}$Ne($\alpha$,$p$)$^{21}$Na rate significantly affects the peak nuclear energy generation rate and the onset temperature of this breakout reaction in these phenomena., Comment: 6 pages, 4 figures

The resonance structure in $^{11}$C is particularly of interest with regard to the astrophysical $^{7}$Be($\alpha$, $\gamma$) reaction, relevant at high temperature, and to the $\alpha$-cluster structure in $^{11}$C. The measurement was to determine unknown resonance parameters for the high excited states of $^{11}$C. In particular, the $\alpha$ decay width can be useful information to discuss $\alpha$ cluster structure in $^{11}$C. New measurements of the $^{7}$Be+$\alpha$ resonant scattering and the $^{7}$Be($\alpha$, $p$)$^{10}$B reaction in inverse kinematics were performed for center-of-mass energy up to 5.5 MeV, and the resonances at excitation energies of 8.9--12.7 MeV in the compound $^{11}$C nucleus were studied. Inelastic scattering of $^{7}$Be+$\alpha$ and the $^{7}$Be($\alpha$, $p_1$)$^{10}$B$^*$ reaction were also studied with a simultaneous $\gamma$-ray measurement. The measurements were performed at the low-energy RI beam facility CRIB (CNS Radioactive Ion Beam separator) of the Center for Nuclear Study (CNS), the University of Tokyo. We obtained excitation functions of $^{7}$Be($\alpha$, $\alpha_0$)$^{7}$Be (elastic scattering), $^{7}$Be($\alpha$, $\alpha_1$)$^{7}$Be$^*$ (inelastic scattering), $^{7}$Be($\alpha$, $p_0$)$^{10}$B, and $^{7}$Be($\alpha$, $p_1$)$^{10}$B$^*$. Many resonances including a new one were observed and their parameters were determined by an R-matrix analysis. The resonances we observed possibly enhance the $^{7}$Be($\alpha$, $\gamma$) reaction rate but in a smaller magnitude than the lower-lying resonances. A new negative-parity cluster band, similar to the one previously suggested in the mirror nucleus $^{11}$B, is proposed.

The evolution of massive stars with very low-metallicities depends critically on the amount of CNO nuclides which they produce. The $^{12}$N($p$,\,$\gamma$)$^{13}$O reaction is an important branching point in the rap-processes, which are believed to be alternative paths to the slow 3$\alpha$ process for producing CNO seed nuclei and thus could change the fate of massive stars. In the present work, the angular distribution of the $^2$H($^{12}$N,\,$^{13}$O)$n$ proton transfer reaction at $E_{\mathrm{c.m.}}$ = 8.4 MeV has been measured for the first time. Based on the Johnson-Soper approach, the square of the asymptotic normalization coefficient (ANC) for the virtual decay of $^{13}$O$_\mathrm{g.s.}$ $\rightarrow$ $^{12}$N + $p$ was extracted to be 3.92 $\pm$ 1.47 fm$^{-1}$ from the measured angular distribution and utilized to compute the direct component in the $^{12}$N($p$,\,$\gamma$)$^{13}$O reaction. The direct astrophysical S-factor at zero energy was then found to be 0.39 $\pm$ 0.15 keV b. By considering the direct capture into the ground state of $^{13}$O, the resonant capture via the first excited state of $^{13}$O and their interference, we determined the total astrophysical S-factors and rates of the $^{12}$N($p$,\,$\gamma$)$^{13}$O reaction. The new rate is two orders of magnitude slower than that from the REACLIB compilation. Our reaction network calculations with the present rate imply that $^{12}$N($p,\,\gamma$)$^{13}$O will only compete successfully with the $\beta^+$ decay of $^{12}$N at higher ($\sim$two orders of magnitude) densities than initially predicted., Comment: 8 figures, 2 tables, Submitted to Physical Review C

The Trojan Horse Method was applied for the first time to a Radioactive Ion Beam induced reaction to study the reaction $^{18}$F(p,$\alpha$)$^{15}$O via the three body reaction $^{18}$F(d,$\alpha$ $^{15}$O)n at the low energies relevant for astrophysics. The abundance of $^{18}$F in Nova explosions is an important issue for the understanding of this astrophysical phenomenon. For this reason it is necessary to study the nuclear reactions that produce or destroy $^{18}$F in Novae. $^{18}$F(p,$\alpha$)$^{15}$O is one of the main $^{18}$F destruction channels. Preliminary results are presented in this paper., Comment: Talk given by Marisa Gulino at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS)

The low-lying states in 106Zr and 108Zr have been investigated by means of {\beta}-{\gamma} and isomer spectroscopy at the RI beam factory, respectively. A new isomer with a half-life of 620\pm150 ns has been identified in 108Zr. For the sequence of even-even Zr isotopes, the excitation energies of the first 2+ states reach a minimum at N = 64 and gradually increase as the neutron number increases up to N = 68, suggesting a deformed sub-shell closure at N = 64. The deformed ground state of 108Zr indicates that a spherical sub-shell gap predicted at N = 70 is not large enough to change the ground state of 108Zr to the spherical shape. The possibility of a tetrahedral shape isomer in 108Zr is also discussed., Comment: 10 pages, 3 figures, Accepted for publication in Phys. Rev. Lett

Over the past three years, we have worked on developing a well-characterized 30S radioactive beam to be used in a future experiment aiming to directly measure the 30S(alpha,p) stellar reaction rate within the Gamow window of Type I X-ray bursts., Comment: 3 pages, 1 figure, Origin of Matter and Evolution of the Galaxies (OMEG10), March 2010, Osaka, Japan

Over the past three years, we have worked on developing a well-characterized 30S radioactive beam to be used in a future experiment aiming to directly measure the 30S(alpha,p) stellar reaction rate within the Gamow window of Type I X-ray bursts. The importance of the 30S(alpha,p) reaction to X-ray bursts is discussed. Given the astrophysical motivation, the successful results of and challenges involved in the production of a low-energy 30S beam are detailed. Finally, an overview of our future plans regarding this on-going project are presented., Comment: 7 pages, 2 figures, 5th European Summer School on Experimental Nuclear Astrophysics, Santa Tecla, Sicily, September 2009