Search results for "Decay chain"
showing 9 items of 39 documents
Two neutral pion photoproduction off the proton between threshold and 800 MeV
1997
Abstract The photoproduction of two neutral pions off the proton has been studied for incident photon energies between E γ = 309 MeV (threshold) and 792 MeV with the TAPS photon spectrometer at the Mainz Microtron MAMI. Both 3γ- and 4γ-events have been analysed in order to deduce the total p ( γ , 2 π 0 ) p cross section. The total cross section is less than 300 nb between threshold and ⋍ 460 MeV, beyond which it starts to rise to a maximum value of about 11 μb at around 750 MeV. For the highest energies it starts to decrease again. The 4γ-sample has been used to reconstruct 2 neutral pions from the above reaction channel by an invariant mass and a missing mass analysis. After reconstructio…
Decay chain information on the newly discovered double charm baryon state $\Xi_{cc}^{++}$
2017
We interprete the new double charm baryon state found by the LHCb Collaboration in the invariant mass distribution of the set of final state particles $(\Lambda_c^+\,K^-\,\pi^+\,\pi^+)$ as being at the origin of the decay chain $\Xi_{cc}^{++} \to \Sigma_c^{++} (\to \Lambda_c^+ \pi^+) +\bar K^{*0} (\to K^- \pi^+)$. The nonleptonic decay $\Xi_{cc}^{++} \to \Sigma_c^{++} + \bar K^{*0}$ belongs to a class of decays where the quark flavor composition is such that the decay proceeds solely via the factorizing contribution precluding a contamination from internal $W$-exchange. We use the covariant confined quark model previously developed by us to calculate the four helicity amplitudes that descri…
Analysis of the semileptonic and nonleptonic two-body decays of the double heavy charm baryon states Ξcc++,Ξcc+ and Ωcc+
2019
We calculate the semileptonic and a subclass of sixteen nonleptonic two-body decays of the double charm baryon ground states Ξcc++,Ξcc+ and Ωcc+ where we concentrate on the nonleptonic decay modes. We identify those nonleptonic decay channels in which the decay proceeds solely via the factorizing contribution precluding a contamination from W exchange. We use the covariant confined quark model previously developed by us to calculate the various helicity amplitudes which describe the dynamics of the 1/2+→1/2+ and 1/2+→3/2+ transitions induced by the Cabibbo-favored effective (c→s) and (d→u) currents. We then proceed to calculate the rates of the decays as well as polarization effects and ang…
Search for universal extra dimensions in ppbar collisions
2012
We present a search for Kaluza-Klein (KK) particles predicted by models with universal extra dimensions (UED) using a data set corresponding to an integrated luminosity of 7.3 fb$^{-1}$, collected by the D0 detector at a $p\bar p$ center of mass energy of 1.96 TeV. The decay chain of KK particles can lead to a final state with two muons of the same charge. This signature is used to set a lower limit on the compactification scale of $R^{-1}>260$ GeV in a minimal UED model.
Joint angular decay distributions in exclusive weak decays of heavy mesons and baryons
1993
We present the results of a comprehensive analysis of the angular decay distributions occurring in the weak exclusive decays of the lowest lying charm and bottom mesons and baryons. We deal with both semileptonic and nonleptonic decays and discuss various decay channels and their subsequent cascade decay chains including lepton mass effects. In the case of baryons we include polarization effects for the parent charm or bottom baryon. We list in table form general formulae which allow one to write down the joint angular decay distributions for the cascade decaysA→B(→b 1+...+b n )+C(→c 1+...+c n ), for all spin casess A ≤1/2 ands B ,s C ≤3/2 for the prominent decays ofB andC. Two examples inv…
Alpha-Photon Coincidence Spectroscopy Along Element 115 Decay Chains
2014
Produced in the reaction 48Ca+243Am, thirty correlated α-decay chains were observed in an experiment conducted at the GSI Helmholzzentrum fur Schwerionenforschung, Darmstadt, Germany. The decay chains are basically consistent with previous findings and are considered to originate from isotopes of element 115 with mass numbers 287, 288, and 289. A set-up aiming specifically for high-resolution charged particle and photon coincidence spectroscopy was placed behind the gas-filled separator TASCA. For the first time, γ rays as well as X-ray candidates were observed in prompt coincidence with the α-decay chains of element 115.
Studies of 225,226U alpha decay chains
2001
Studies of 225,226U α -decay chains produced via heavy ion induced fusion reactions of 22Ne + 208Pb → 230U and of 18O + 208Pb → 226Th were carried out using the JYFL gas-filled magnetic recoil separator RITU. The data obtained for α -decays of 225,226U, 221,222Th, 218Ra and 213Rn concerning their α -particle energies, half-lives and α -decay fine structures are compared to previous investigations. peerReviewed
Comment on 'Analysis of decay chains of superheavy nuclei produced in the 249Bk + 48Ca and 243Am + 48Ca reactions'
2019
Zlokazov and Utyonkov (2017 J. Phys. G: Nucl. Part. Phys. 44 075107) question the validity of the methods and conclusions presented by Forsberg et al (2016 Nucl. Phys. A 953 117). In this comment, we argue that the criticism is invalid. nonPeerReviewed
Structure of superheavy nuclei along decay chains of element 115
2014
[Introduction] A recent high-resolution α , X -ray, and γ -ray coincidence-spectroscopy experiment offered the first glimpse of excitation schemes of isotopes along α -decay chains of Z = 115. To understand these observations and to make predictions about shell structure of superheavy nuclei below 288 115, we employ two complementary mean-field models: the self-consistent Skyrme energy density functional approach and the macroscopic-microscopic Nilsson model. We discuss the spectroscopic information carried by the new data. In particular, candidates for the experimentally observed E 1 transitions in 276 Mt are proposed. We find that the presence and nature of low-energy E 1 transitions in w…