Decay Branching Ratios Research Articles

Doppler broadening in Mg20(βpγ)Ne19 decay

Background: The $^{15}$O($\alpha ,\gamma$)$^{19}$Ne bottleneck reaction in Type I x-ray bursts is the most important thermonuclear reaction rate to constrain experimentally, in order to improve the accuracy of burst light-curve simulations. A proposed technique to determine the thermonuclear rate of this reaction employs the $^{20}$Mg($\beta p\alpha$)$^{15}$O decay sequence. The key $^{15}$O($\alpha ,\gamma$)$^{19}$Ne resonance at an excitation of 4.03 MeV is now known to be fed in $^{20}$Mg($\beta p\gamma$)$^{19}$Ne; however, the energies of the protons feeding the 4.03 MeV state are unknown. Knowledge of the proton energies will facilitate future $^{20}$Mg($\beta p \alpha$)$^{15}$O measurements. Purpose: To determine the energy of the proton transition feeding the 4.03 MeV state in $^{19}$Ne. Method: A fast beam of $^{20}$Mg was implanted into a plastic scintillator, which was used to detect $\beta$ particles. 16 high purity germanium detectors were used to detect $\gamma$ rays emitted following $\beta p$ decay. A Monte Carlo method was used to simulate the Doppler broadening of $^{19}$Ne $\gamma$ rays and compare to the experimental data. Results: The center of mass energy between the proton and $^{19}$Ne, feeding the 4.03 MeV state, is measured to be 1.21${^{+0.25}_{-0.22}}$ MeV, corresponding to a $^{20}$Na excitation energy of 7.44${^{+0.25}_{-0.22}}$ MeV. Absolute feeding intensities and $\gamma$-decay branching ratios of $^{19}$Ne states were determined including the 1615 keV state. A new $\gamma$ decay branch from the 1536 keV state in $^{19}$Ne to the ground state is reported. The lifetime of the 1507 keV state in $^{19}$Ne is measured to be 4.3${^{+1.3}_{-1.1}}$ ps resolving discrepancies in the literature. Conflicting $^{20}$Mg($\beta p$) decay schemes in published literature are clarified.

Search for decay modes of heavy and superheavy nuclei * * Supported by the Turkish Science and Research Council (TÜBİTAK) with Grant Number 118R028

Spontaneous fission (SF) with a new formula based on a liquid drop model is proposed and used in the calculation of the SF half-lives of heavy and superheavy nuclei (Z= 90–120). The predicted half-lives are in agreement with the experimental SF half-lives. The half-lives of decay (AD) for the same nuclei are obtained by using the Wentzel-Kramers-Brillouin (WKB) method together with Bohr-Sommerfeld (BS) quantization condition considering the isospin-dependent effects for the cosh potential. The decay modes and branching ratios of superheavy nuclei (Z= 104-118) with experimental decay modes are obtained, and the modes are compared with the experimental ones and with the predictions found in the literature. Although some nuclei have predicted decay modes that are different from their experimental decay modes, decay modes same as the experimental ones are predicted for many nuclei. The SF and AD half-lives, branching ratios, and decay modes are obtained for superheavy nuclei (Z= 119–120) with unknown decay modes and compared with the predictions obtained in a previous study. The present results provide useful information for future experimental studies performed on both the AD and SF of superheavy nuclei.

Search for production of an invisible dark photon in \u03c00 decays

The results of a search for π0 decays to a photon and an invisible massive dark photon at the NA62 experiment at the CERN SPS are reported. From a total of 4.12 × 108 tagged π0 mesons, no signal is observed. Assuming a kinetic-mixing interaction, limits are set on the dark photon coupling to the ordinary photon as a function of the dark photon mass, improving on previous searches in the mass range 60–110 MeV/c2. The present results are interpreted in terms of an upper limit of the branching ratio of the electro-weak decay {pi}^0to gamma nu overline{nu} , improving the current limit by more than three orders of magnitude.

Impact of Z′ boson on lepton flavor violating decays

Recently, some small hints of lepton flavor violating (LFV) decays have been probed in different colliders and accelerators. Although these processes are forbidden in the Standard Model (SM), observation of LFV decays are considered as good probes to test theory beyond the SM. In this paper, we study some LFV decays, e.g. three-body decay channels of [Formula: see text] lepton like [Formula: see text], [Formula: see text] and two-body decays of B meson and [Formula: see text] lepton like [Formula: see text] and [Formula: see text] in [Formula: see text] model. We calculate the branching ratio of the above decays considering the effect of both [Formula: see text] and [Formula: see text]-mediated flavor-changing neutral-current (FCNC).

Semileptonic decays of anti-triplet charmed baryons

We study the semileptonic decays Bc→Bnℓ+νℓ where Bc(n) is the anti-triplet-charmed (octet) baryon with the SU(3)f flavor symmetry and helicity formalism. In particular, we present the decay branching ratios of Bc→Bnℓ+νℓ in three scenarios: (a) an exact SU(3)f symmetry with equal masses for the anti-triplet-charmed (octet) baryon states of Bc (Bn), (b) SU(3)f parameters without the baryonic momentum-transfer dependence, and (c) SU(3)f with baryonic transition form factors in the heavy quark limit. We show that our results are all consistent with the existing data. Explicitly, we predict that B(Ξc+→Ξ0e+νe)=(11.9±1.3,9.8±1.1,10.7±0.9)×10−2 and B(Ξc0→Ξ−e+νe)=(3.0±0.3,2.4±0.3,2.7±0.2)×10−2 in the scenarios (a), (b) and (c) agree with the data of (14.0−8.7+8.3)×10−2 and (5.6±2.6)×10−2 from the CLEO Collaboration, respectively. In addition, we obtain that B(Λc+→ne+νe)=(2.8±0.4,4.9±0.4,5.1±0.4)×10−3 in (a), (b) and (c). We also examine the longitudinal asymmetry parameters of α(Bc→Bnℓ+νℓ), which are sensitive to the different scenarios with SU(3)f. Some of the decay branching ratios and asymmetries can be observed by the ongoing experiments at BESIII and LHCb as well as the future searches by BELLEII.

Investigation of the spontaneous fission properties of neutron-deficient nobelium isotopes

In the last years we carried out several experiments aimed to investigate properties of short-lived SF isotopes. The neutron-deficient isotopes of nobelium were produced in fusion-evaporation reactions using 206,208 Pb targets and an intense 48 Ca-beam. Fusion-evaporation residues were separated by the SHELS separator and implanted into a large-area double-sided (48 × 48) strip silicon detector surrounded by 3 He-based neutron counters. Half-lives and decay branching ratios for 252,254 No isotopes were measured. The average number of neutrons per spontaneous fission of 254 No determined for the first time.

Decayϕ→Zγγ(ϕ=h,H,A) in the minimal supersymmetric standard model

The decays of the CP-even ($h,\,H$) and the CP-odd ($A$) Higgs bosons $h,\,H,\,A\to Z\gamma\gamma$ are calculated in the context of the minimal supersymmetric standard model (MSSM), where they are induced at the one-loop level via box and reducible Feynman diagrams. For the numerical evaluation of the branching ratios we employ the decoupling limit and consider values for the MSSM parameters still consistent with the current experimental data. We consider a particular scenario for the radiative corrections to the Higgs boson masses, dubbed hMSSM, which leads to only two free parameters, namely $m_A$ and $\tan\beta$. We found that the branching ratio of the $CP$-odd Higgs boson decay $A\to Z\gamma\gamma$ can reach values up to $10^{-8}$ for $m_A=750$ GeV, which is three order of magnitude smaller than that of the $A\to\gamma\gamma$ channel. On the other hand, the branching ratio of the $H\to Z\gamma\gamma$ decay is of the order of $10^{-7}$ for large values of $m_H$ and small values of $\tan\beta$, which is comparable with the branching ratio of the $H\to Z\gamma$ channel. As far as the branching ratio of the SM-like Higgs boson decay $h\to Z\gamma\gamma$ is concerned, it is considerably suppressed, of the order of $10^{-11}$.

Effective-field-theory arguments for pursuing lepton-flavor-violating K decays at LHCb

We provide general effective-theory arguments relating present-day discrepancies in semi-leptonic $B$-meson decays to signals in kaon physics, in particular lepton-flavour violating ones of the kind $K \to (\pi) e^\pm \mu^\mp$. We show that $K$-decay branching ratios of around $10^{-12} - 10^{-13}$ are possible, for effective-theory cutoffs around $5-15$ TeV compatible with discrepancies in $B\to K^{(\ast)} \mu\mu$ decays. We perform a feasibility study of the reach for such decays at LHCb, taking $K^+ \to \pi^+ \mu^\pm e^\mp$ as a benchmark. In spite of the long lifetime of the $K^+$ compared to the detector size, the huge statistics anticipated as well as the overall detector performance translate into encouraging results. These include the possibility to reach the $10^{-12}$ ballpark, and thereby significantly improve current limits. Our results advocate LHC's high-luminosity Upgrade phase, and support analogous sensitivity studies at other facilities. Given the performance uncertainties inherent in the Upgrade phase, our conclusions are based on a range of assumptions we deem realistic on the particle identification performance as well as on the kinematic reconstruction thresholds for the signal candidates.

Singly Cabibbo suppressed decays of [formula omitted] with SU(3) flavor symmetry

We analyze the weak processes of anti-triplet charmed baryons decaying to octet baryons and mesons with the SU(3) flavor symmetry and topological quark diagram scheme. We study the decay branching ratios without neglecting the contributions from O(15‾) for the first time in the SU(3) flavor symmetry approach. The fitting results for the Cabibbo allowed and suppressed decays of Λc+ are all consistent with the experimental data. We predict all singly Cabibbo suppressed decays. In particular, we find that B(Λc+→pπ0)=(1.3±0.7)×10−4, which is slightly below the current experimental upper limit of 2.7×10−4 and can be tested by the ongoing experiment at BESIII as well as the future one at Belle-II.

Update on energies and widths in Be13

I have compared new experimental information on resonances in $^{13}\mathrm{Be}$ with results of theoretical calculations. For the $1/{2}^{+}$ resonance at 0.86 MeV, the reported width of 1.70(15) MeV is considerably larger than the single-particle limit of 1.3 MeV. For the first $5/{2}^{+}$, the calculated width and ${2}^{+}$ branching ratio for neutron decay are both in rough agreement with the data. I discuss the possibility that events from decay of the second $5/{2}^{+}$ to $^{12}\mathrm{Be}({2}^{+})$ could contribute to the 0.86-MeV peak. If the 4.0-MeV resonance is indeed $3/{2}^{+}$, then its width should be considerably larger than reported.

Up-conversion Luminescence Properties of Er3+/Yb3+ Co-Doped Oxyfluoride Glass Ceramic

Er3+/Yb3+ co-doped glass ceramic samples were prepared by melt-quenching method utilizing nominal composition 52SiO2–8Na2CO3–16Al2O3–33NaF-3LuF3-0.15Yb2O3 − 0.03Er2O3 (in mol%). The spectral characteristic was studied based on Judd-Ofelt theory. Spectrum intensity parameters Ωλ(λ = 2,4,6) were calculated on the basis of the absorption spectrum. The theoretical and experimental oscillator strengths were calculated according to the spectrum intensitty parameters, and the root mean square deviation (δrms) of glass ceramic sample was 4.28 × 10−6. The parameters such as transition probability, decay branching ratios and level lifetime of Er3+ were obtained. Lifetimes of metastable level 4I13/2 and 4I11/2 in as-prepared samples are respectively 11.64 and 13.61 ms which are suitable for up-conversion intermediate levels. Decay branching ratio of 4I13/2→4I15/2 is nearly 100% in Er3+/Yb3+ co-doped oxyfluoride glass ceramic samples which can be used to produce 1543 nm laser. Under the excitation of 980 nm diode laser, up-conversion luminescence is observed at the wavelength of 549 nm and (653, 664) nm, corresponding to the radiative transitions of Er3+:4S3/2→4I15/2and 4F9/2→4I15/2, respectively. The numbers of absorbed photons in the transition process of Er3+/Yb3+ co-doped oxyfluoride glass ceramic samples are estimated at 1.99 and 2.06 respectively according to the relationship between the up-conversion transmitting power and the 980 nm LD laser power. It is determined that the transition process of Er3+/Yb3+ co-doped oxyfluoride glass ceramic samples is two-photon absorption process.

HDECAY: Twenty++ years after

The program HDECAY determines the partial decay widths and branching ratios of the Higgs bosons within the Standard Model with three and four generations of fermions, including the case when the Higgs couplings are rescaled, a general two-Higgs doublet model where the Higgs sector is extended and incorporates five physical states and its most studied incarnation, the minimal supersymmetric Standard Model (MSSM) with real soft SUSY-breaking parameters. The program addresses all decay channels including the dominant higher-order effects such as radiative corrections and multi-body channels. Since the first launch of the program, more than twenty years ago, important aspects and new ingredients have been incorporated. In this update of the program description, some of the developments are summarized while others are discussed in some detail. New version program summaryProgram Title: HDECAYProgram Files doi:http://dx.doi.org/10.17632/3ggyvkjz95.1Licensing provisions: GPLv2Programming language: FORTRAN77Journal reference of previous version: Comp. Phys. Comm. 108 (1998) 56-74.Does the new version supersede the previous version?: YesReasons for the new version: Major updates and extensionsSummary of revisions: Since the first release of the original version of the program some bugs have been fixed, a number of improvements and new theoretical calculations have been implemented. The logbook of all modifications and the most recent version 6.52 of the program can be found on the web page http://tiger.web.psi.ch/hdecay/.Nature of problem: Decay widths and branching ratios for Higgs bosons decays in the Standard Model with three and four generations of fermions and rescaled couplings, a general two-Higgs doublet model and the Minimal Supersymmetric Standard Model are calculated numerically, including loop corrections according to the current theoretical knowledge.Solution method: One- and two-dimensional numerical integration of analytic formulae for Higgs boson decays into off-shell particles. All other decay widths are calculated analytically. The transition between off-shell and on-shell decays is performed by a linear interpolation.

Measurements of lepton universality at LHCb

Lepton universality violation would represent a signal of physics beyond the Standard Model. Anomalies have been observed in the measurement of the branching ratios of semileptonic decays of beauty mesons in third-generation leptons. This contribution reports on the measurements of the observable $R(D^{\ast -}) = B(B^0 \rightarrow D^{\ast -} \tau^+ \nu _\tau)/B(B^0 \rightarrow D^\ast - \mu^+ \nu_\mu)$ and $R(J/\psi)$ = $B(B^+_c \rightarrow J/\psi \tau^+ \nu_\tau)/B(B^+_c \rightarrow J/\psi \mu^+ \nu_\mu)$ performed at LHCb with data collected during the Run 1 of the LHC.

Chlorogenic acid and gallic acid elevate pain sensitivity threshold in olfactory bulbectomised rats

The polarization observables T,E,P,H, and G in photoproduction of η mesons off protons are measured for photon energies from threshold to W=2400 MeV (T), 2280 MeV (E), 1620 MeV (P,H), or 1820 MeV (G), covering nearly the full solid angle. The data are compared to predictions from the SAID, MAID, JüBo, and BnGa partial-wave analyses. A refit within the BnGa approach including further data yields precise branching ratios for the Nη decay of nucleon resonances. A Nη-branching ratio of 0.33±0.04 for N(1650)1/2− is found, which reduces the large and controversially discussed Nη-branching ratio difference of the two lowest mass JP=1/2−-resonances significantly.

An Improved Analysis of Masses and Decay Constants of Heavy Flavour Mesons within Variational Approach

We employ the variational method to study the properties such as masses, decay constants, oscillation frequency and branching ratios of leptonic decays of heavy flavour mesons with linear cum coulomb Cornell potential. Gaussian function, Coulomb wave function and Airy function are taken as the trial wave-function of variational method in this study. Our analysis suggests that Gaussian trial wave-function provides results which are in close proximity with the experimental results. We also make a comparison with the results from QCD Sum rules and lattice QCD, as well as with recent PDG data.

Four α-particles as a final state of 16O* Quasi Projectile decay

Four α-particles as a final state of 16O* quasi-projectile decayproduced in peripheral 16O+12C reactions at 130 MeV is thoroughly studied. The differentdecay channels leading to the four α-particles final state are reconstructed by carrying out an event-by-event analysis of α correlations in the population of intermediate 8Be and 12C. Although small, a non negligible contribution due to 8Begs evaporation is found.A comparison between predictions of an accurate Hauser-Feshbach decay code and branching ratios of the different decay channels is performed. Significant deviations are observed, among these the Hoyle state population which is considerably lower than the one predicted according to the statistical model, thus suggesting possible structure effects in the Coulomb barrier and/or in the transmission coefficients.

Bs → K*0 decay form factors from covariant confined quark model

We evaluate Bs → K*0 transition form factors in the full kinematical region within the covariant confined quark model. The calculated form factors can be used to calculate the Bs → K*0 μ+μ– rare decay branching ratio, which was recently measured by LHCb collaboration.

Witten’s loop in the minimal flipped SU(5) unification revisited

In the simplest potentially realistic renormalizable variants of the flipped $SU(5)$ unified model the right-handed neutrino masses are conveniently generated by means of the Witten's two-loop mechanism. As a consequence, the compactness of the underlying scalar sector provides strong correlations between the low-energy flavor observables such as neutrino masses and mixing and the flavor structure of the fermionic currents governing the baryon and lepton number violating nucleon decays. In this study, the associated two-loop Feynman integrals are fully evaluated and, subsequently, are used to draw quantitative conclusions about the central observables of interest such as the proton decay branching ratios and the absolute neutrino mass scale.

Time-Like Baryon Transitions in Hadroproduction

The Dalitz decay of baryonic resonances (B $$\rightarrow $$ N $$e^+e^-$$ ) gives access to the time-like electromagnetic structure of baryonic transitions at small positive values of the squared four momentum transferred. Such processes were investigated by the HADES collaboration in elementary hadronic interactions. The Dalitz decay branching ratio of the $$\varDelta (1232)$$ resonance has been measured for the first time in pp reactions at 1.25 GeV beam energy. At higher energies, the $$e^+e^-$$ emission from baryonic decays is shown to be sensitive to transition form factors of the Vector Dominance Model type. Using a pion beam, Dalitz decays of baryonic resonances can be measured more directly. In addition, the simultaneous measurement of hadronic channels provides a new data base for baryon spectroscopy issues. Preliminary results of a test experiment in the N(1520) region are shown, together with prospects for higher resonance studies. A project of measuring hyperon Dalitz decays at GSI and later on at FAIR is also discussed. The study of Dalitz decays of baryon resonances and, in particular, the role of the $$\rho $$ meson brings useful constraints for the study of medium effects also investigated by the HADES collaboration in reactions with nuclei.

The ORNL analysis technique for extracting [formula omitted]-delayed multi-neutron branching ratios with BRIKEN

Many choices are available in order to evaluate large radioactive decay networks. There are many parameters that influence the calculated β-decay delayed single and multi-neutron emission branching fractions. We describe assumptions about the decay model, background, and other parameters and their influence on β-decay delayed multi-neutron emission analysis. An analysis technique, the ORNL BRIKEN analysis procedure, for determining β-delayed multi-neutron branching ratios in β-neutron precursors produced by means of heavy-ion fragmentation is presented. The technique is based on estimating the initial activities of zero, one, and two neutrons occurring in coincidence with an ion-implant and β trigger. The technique allows one to extract β-delayed multi-neutron decay branching ratios measured with the 3He BRIKEN neutron counter. As an example, two analyses of the β-neutron emitter 77Cu based on different a priori assumptions are presented along with comparisons to literature values.