WorldWideScience

Sample records for nonmesonic hypernuclear decay

  1. Is nuclear structure relevant to non-mesonic hyper-nuclear weak decay?

    International Nuclear Information System (INIS)

    Wu, H.C.; Ponce, W.A.

    2001-01-01

    Full text: The focus of existing studies of the non-mesonic hypernuclear weak decay has been on the two-body process ΛN → NN, whereas the investigation on effects of nuclear structure is relatively rare. Some authors even assumed that the nuclear structure is irrelevant to the non mesonic hypernuclear weak decay. In this work we try to reveal the importance of nuclear structure in non mesonic weak decay of the Λ - hypernuclei through examining the relevance of many-body properties as well as the single particle properties of different nuclear models. For hypernucleus 12 Λ C, a comparison between the L-S coupling (realized by the symmetry model SU(4) x SU(3) and the j-j coupling (realized by the single particle shell model) gives an estimate of the range of nuclear structure effects. It has been found that while the total decay rate is almost independent of coupling schemes, the ratio Γn/Γp has a difference of around 30% between the two limits of many-body wave functions. There also exists a strong dependence of the total decay rate and the ratio Γn/Γp on the single particle properties of shell model, such as the binding energy of nucleon and the parameters of harmonic oscillator orbits, etc. Therefore, one may conclude that the nuclear structure is relevant to the non-mesonic hypernuclear weak decay. With the mechanism of ΛN → NN transition being restricted to one pion exchange (OPE) only, the consequences of possible contribution from the ΔI = 3/2 channel is investigated in a phenomenological manner. It has been shown that a mixing of ΔI = 3/2 channel will change the total decay rate as well as the ratio Γn/Γp considerably. (Author)

  2. Possible violation of the ΔI=1/2 rule in non-mesonic hypernuclear weak decay

    International Nuclear Information System (INIS)

    Schumacher, R.A.

    1991-01-01

    The weak decays of strange mesons and free hyperons strongly favor ΔI=1/2 amplitudes over ΔI=3/2 amplitudes. It is now known to what extent this rule applies to the non-mesonic interactions of the type Λp → np and Λn → nn. This paper examines existing data on non-mesonic decays of light hypernuclei in order to obtain a quantitative estimate of the relative strength of the two isospin channels., The data show that a pure ΔI=1/2 decay amplitude is ruled out at the 1.6σ level, and favor a solution where either: (1) both isospin channels contribute about equally, or (2) the ΔI=3/2 channel dominates by an order of magnitude

  3. Is nuclear structure relevant to non-mesonic hyper-nuclear weak decay?

    International Nuclear Information System (INIS)

    Wu, H.C.; Aristizabal, M.F.; Ponce, W.A.

    2002-01-01

    This work studies the relevance of nuclear structure in the non-mesonic weak decay of Λ-hypernuclei, with the mechanism of ΛN → NN transition being restricted to one pion exchange (OPE) only. As an application, for the hypernucleus Λ 12 C a comparison between the L-S coupling and the j-j coupling gives an estimate of the range of nuclear structure effects. A considerable dependence is found of the total decay rate and the ratio Γ n /Γ p on the single particle properties of nuclear models. The possible contribution from the ΔI = 3/2 channel is investigated in a phenomenological manner. (author)

  4. Nonmesonic decays and lifetimes of hypernuclei

    International Nuclear Information System (INIS)

    Itonaga, K.; Ueda, T.; Motoba, T.

    2002-01-01

    The nonmesonic decay rates and the lifetimes of hypernuclei of mass A=4-209 are extensively calculated based on the 1π, correlated-2π, and 1ω exchange potentials. Two types of new hyperon-nucleon potentials have been constructed in which the two pions are correlated and coupled to ρ and/or σ in the exchange process. The roles of these potentials and 1ω exchange potential are discussed. The theoretical decay rates are consistent with the existing data for s-shell and p-shell hypernuclei within the present model. The calculated decay rate increases gradually up to A≅60 and then tends to be almost constant for A(greater-or-similar sign)60. The A-dependent behavior of the hypernuclear lifetimes tends to be constant over the mass region A>30 of hypernuclei in our model. It is most remarkable that the cooperative effect of the correlated-2π and 1ω exchanges enhances the neutron-stimulated decay rate Γ n (proton-stimulated one Γ p ) by 400-450 % (20-30 %) with respect to the standard 1π-exchange estimate for A>5. As a result the Γ n /Γ p ratios for light-to-heavy hypernuclei are calculated to be 0.4-0.5, which values are several times larger than the 1π-exchange estimate. Although the experimental ratios seem still about two times larger than these theoretical values, it has revealed that the representative 2π-exchange and 1ω exchange mechanisms give rise to a clear improvement on the Γ n /Γ p ratios

  5. Decay of hypernuclei

    International Nuclear Information System (INIS)

    Bando, H.

    1985-01-01

    The pionic and non-mesonic decays of hypernuclei are discussed. In the first part, various decay processes which could be useful to obtain information of hypernuclear structure are discussed. The experimental data concerning the pionic and non-mesonic decays are discussed in the second part. As the experimental data, there are only few lifetime data and some crude data on the non-mesonic to π decay ratio. In the third and the fourth parts, some theoretical analyses are made on the pionic and the nonmesonic decays. DDHF calculation was performed for Λ and N systems by using Skyrme type ΛN and NN effective interactions. A suppression factor of the order of 10 -3 for A nearly equal 100 was obtained. (Aoki, K.)

  6. Weak decay of Λ hypernuclei. Recent results from Korea-Japan collaboration research on hypernuclear physics at KEK

    International Nuclear Information System (INIS)

    Bhang, H.; Park, H.; Kim, J.H.

    1999-01-01

    Through the last 7-8 years of collaboration with the SKS hypernuclear physics group at KEK, we have concentrated on the measurement of Λ hypernuclear decays. Non-mesonic weak decay mode of Λ hypernucleus is especially interesting and has been the central theme of our collaboration researches. We have measured the weak decay observables of Λ hypernuclei over a broad mass range, A = 11 - 89, from which their characteristic mass dependences are clearly observed. The lifetime decreases slightly from that of free Λ and quickly saturates at ∼80 percent of τ Λ in free space as the mass number increases. The preliminary results on Γ n /Γ p confirm the domination of the ratio Γ n over Γ p and restate the existing discrepancy between the values of experimental data and theoretical calculation. Much improved neutron detection efficiency in the experiment, KEK-PS E369, will shed light on the understanding of this puzzling ratio. The collaboration produced a series of excellent data on the decay. (author)

  7. Nonmesonic weak decay of the hypertriton

    International Nuclear Information System (INIS)

    Bennhold, C.; Ramos, A.; Aruliah, D.A.; Oelfke, U.

    1992-01-01

    The nonmesonic weak decay of Λ 3 H is evaluated microscopically in the pion exchange model. The correlated three-body wave function of the hypertriton is approximated by a bound Λ-deuteron system obtained by averaging the YN interaction over the deuteron wave function. The relevant matrix elements are calculated in momentum space. The resulting decay rate is 4.9% of the free Λ decay rate

  8. Partial Widths of Nonmesonic Weak Decays of Lambda-Hypernuclei

    CERN Document Server

    Kuzmin, V A

    2002-01-01

    It is shown that the phenomenological matrix elements completely describing \\Lambda N \\to NN weak interaction in the 1p-shell nuclei can be obtained from the partial widths of nonmesonic decays of ^{10}_{\\Lambda}Be and ^{10}_{\\Lambda}B hypernuclei. It is shown that the uncertainties related to the description of nuclear structure are not essential for this task.

  9. The weak decay of helium hypernuclei

    International Nuclear Information System (INIS)

    Athanas, M.J.

    1992-08-01

    A Λ hyperon replaces a neutron in a nucleus to form a hypernucleus via the A X(K - , π - ) Λ A X reaction at 750 MeV/c (Brookhaven Experiment 788). The free Λ decay rates Γ(Λ → pπ - ) and Γ(Λ → nπ 0 ) are diminished due to Pauli blocking; but a non-mesonic decay mode, nucleon stimulated decay NΛ → Nn, is present and is detected via the energetic decay nucleon(s) (∼ 400MeV/c). Measurements of the various hypernuclear decay rates Γ(Λ → pπ - ), Γ(Λ → nπ 0 ) and Γ(Λn → nn) provides insight into the strong modification of the weak interaction such as the baryon-baryon ΔI =1/2 rule. The hypernuclear state is isolated by momentum analysis of (K - , π - ) target reaction. Out-of-beam large volume scintillation detectors and tracking chambers axe used to make particle identification of the hypernuclear decay products by time-of-flight, dE/dx, and range. The kinetic energy of the decay neutrons are measured by time of flight using the large volume 100 element neutron detector system. The hypernuclear lifetime is directly measured using precision scintillator counters and tracking chambers. Measurements of the various decay rates as well as the total lifetime are discussed for Λ 4 He

  10. The weak decay of helium hypernuclei

    Energy Technology Data Exchange (ETDEWEB)

    Athanas, Michael J. [Carnegie-Mellon Univ., Pittsburgh, PA (United States)

    1992-08-01

    A Λ hyperon replaces a neutron in a nucleus to form a hypernucleus via the AX(K-, π-) $A\\atop{Λ}$X reaction at 750 MeV/c (Brookhaven Experiment 788). The free Λ decay rates Γ(Λ → pπ-) and Γ(Λ → nπ0) are diminished due to Pauli blocking; but a non-mesonic decay mode, nucleon stimulated decay NΛ → Nn, is present and is detected via the energetic decay nucleon(s) (~ 400MeV/c). Measurements of the various hypernuclear decay rates Γ(Λ → pπ-), Γ(Λ → nπ0) and Γ(Λn → nn) provides insight into the strong modification of the weak interaction such as the baryon-baryon ΔI ={1/2} rule. The hypernuclear state is isolated by momentum analysis of (K-, π-) target reaction. Out-of-beam large volume scintillation detectors and tracking chambers axe used to make particle identification of the hypernuclear decay products by time-of-flight, dE/dx, and range. The kinetic energy of the decay neutrons are measured by time of flight using the large volume 100 element neutron detector system. The hypernuclear lifetime is directly measured using precision scintillator counters and tracking chambers. Measurements of the various decay rates as well as the total lifetime are discussed for $4\\atop{Λ}$He.

  11. Hypernuclear weak decay puzzle

    International Nuclear Information System (INIS)

    Barbero, C.; Horvat, D.; Narancic, Z.; Krmpotic, F.; Kuo, T.T.S.; Tadic, D.

    2002-01-01

    A general shell model formalism for the nonmesonic weak decay of the hypernuclei has been developed. It involves a partial wave expansion of the emitted nucleon waves, preserves naturally the antisymmetrization between the escaping particles and the residual core, and contains as a particular case the weak Λ-core coupling formalism. The extreme particle-hole model and the quasiparticle Tamm-Dancoff approximation are explicitly worked out. It is shown that the nuclear structure manifests itself basically through the Pauli principle, and a very simple expression is derived for the neutron- and proton-induced decays rates Γ n and Γ p , which does not involve the spectroscopic factors. We use the standard strangeness-changing weak ΛN→NN transition potential which comprises the exchange of the complete pseudoscalar and vector meson octets (π,η,K,ρ,ω,K * ), taking into account some important parity-violating transition operators that are systematically omitted in the literature. The interplay between different mesons in the decay of Λ 12 C is carefully analyzed. With the commonly used parametrization in the one-meson-exchange model (OMEM), the calculated rate Γ NM =Γ n +Γ p is of the order of the free Λ decay rate Γ 0 (Γ NM th congruent with Γ 0 ) and is consistent with experiments. Yet the measurements of Γ n/p =Γ n /Γ p and of Γ p are not well accounted for by the theory (Γ n/p th p th > or approx. 0.60Γ 0 ). It is suggested that, unless additional degrees of freedom are incorporated, the OMEM parameters should be radically modified

  12. Correlation effects on the nonmesonic weak decay of the Λ hyperon in nuclear matter

    Science.gov (United States)

    Robertson, N. J.; Dickhoff, W. H.

    2005-08-01

    The nonmesonic weak decay of a Λ hyperon is studied in nuclear matter. Special emphasis is placed on a consistent treatment of correlations introduced by the strong interaction on its weak counterpart. The latter is described by the exchange of mesons between the initial ΛN state and the final NN one. The weak decay is studied in terms of the weak self-energy, which allows a systematic evaluation of short-range and tensor correlation effects that are determined by a realistic hyperon-nucleon interaction. The admixture of ΣN components through the strong interaction is also included in the calculation of the Λ decay properties. Calculations for the ratio of the neutron-induced partial width to the corresponding proton-induced one, Γn/Γp, are discussed in connection with recent experimental results.

  13. Hypernuclear weak decay experiments at KEK: n-n and n-p coincidence measurement

    International Nuclear Information System (INIS)

    Outa, H.; Ajimura, S.; Aoki, K.; Banu, A.; Bhang, H.C.; Fukuda, T.; Hashimoto, O.; Hwang, J.I.; Kameoka, S.; Kang, B.H.; Kim, E.H.; Kim, J.H.; Kim, M.J.; Maruta, T.; Miura, Y.; Miyake, Y.; Nagae, T.; Nakamura, M.; Nakamura, S.N.; Noumi, H.; Okada, S.; Okayasu, Y.; Park, H.; Saha, P.K.; Sato, Y.; Sekimoto, M.; Takahashi, T.; Tamura, H.; Tanida, K.; Toyoda, A.; Tsukada, K.; Watanabe, T.; Yim, H.J.

    2005-01-01

    We performed a coincidence measurement of two nucleons emitted from the nonmesonic weak decay (NMWD) of 5 Λ He and 12 Λ C formed via the (π+,K+) reaction. In both of n+p and n+n pair coincidence spectra, we observed a clean back-to-back correlation coming from the two-body decay of Λp->np and Λn->nn, respectively. We obtained the ratio of the nucleon pair numbers, Nnn/Nnp ( 5 Λ He)=0.45-bar +/--bar 0.11-bar (stat)-bar +/--bar 0.03-bar (syst) in the kinematic region of cosθNN-0.8. Since each decay mode was exclusively detected, the measured ratio should be close to the ratio of Γ(Λp->nn)/Γ(Λn->np). The Γn/Γp ratio was measured also for the NMWD of 12 Λ C. It is also close to 0.5. Those ratios are consistent with recent theoretical calculations based on the heavy meson/direct quark exchange picture

  14. AN HISTORICAL OVERVIEW OF THE IMPORTANCE OF THE WEAK DECAY OF HYPERNUCLEI

    International Nuclear Information System (INIS)

    GIBSON, B.F.

    2001-01-01

    Weak decay of hypernuclei, first cousin to the β-decay of conventional, nonstrange nuclei, was initially observed in the 1950s. Pionic decay rates have proven a challenge--to reconcile nuclear decay rates with that of free λ decay. Pauli blocking of the decay nucleon plays an important role. Nonmesonic decay provides our only practical means of exploring the four-fermion, strangeness-changing NΛ → NN weak interaction. The NΛρ vertex can be investigated in no other way. The large momentum transfer in the nonmesonic decay process suggests a means to probe short distance aspects of the interaction, possibly revealing baryon substructure effects. Whether the ΔI = 1/2 rule, which governs free Λ decay, also applies to the nonmesonic decay process remains an open question. The free Λ does not decay by emission of a π + ; the π + decay of 4 He is a puzzle. Finally, the weak decay of strangeness -2 hypernuclei is an important topic, because the pionic decay process is central to current efforts to seek and identify ΛΛ hypernuclei

  15. Unified description of quasi-free and resonant processes of hypernuclear production and decay

    International Nuclear Information System (INIS)

    Wuensch, R.

    1992-03-01

    We review a unified description of resonant and quasi-free hypernuclear production reactions on the basis of the continuum shell-model. Both reaction mechanisms are considered as boundary cases of the same process. We apply the model to the (K - , π) and to the (π, K + ) reaction on light target nuclei. Particular attention is given to the consequences of the shallow hyperon-nucleus potential. Hypernuclear disintegration by baryon emission is considered as transition from the bound to the unbound part of the configurational space. (orig.)

  16. A probable example of a nonmesonic double hypernucleus

    CERN Document Server

    Mondal, A S; Husain, A; Kasim, M M

    1975-01-01

    A search is made to identify hypernuclear species with two or more decay centres in nuclear emulsion exposed to a separated beam of 3.0 GeV/c K/sup -/-mesons at the CERN Proton Synchrotron. In a sample of 493 hypernuclei one event has been observed whose most probable interpretation turns out to be /sup 31/Si/sub Lambda Lambda / with the successive decay modes /sup 31/Si/sub Lambda Lambda / to /sup 14/C/sub Lambda /+/sup 16/O+n, followed by /sup 14/C/sub Lambda / to /sup 4/He+ /sup 3/He+/sup 3/He+/sup 2/H+/sup 1/H+n, and binding energy B/sub Lambda Lambda /=(38.2+or-6.3) MeV. (18 refs).

  17. Theoretical aspects of the weak decay of hypernuclei

    International Nuclear Information System (INIS)

    Dubach, J.

    1986-01-01

    The present status of theoretical descriptions of mesonic (Λ → Nπ) and non-mesonic (ΛN → NN) decay modes of hypernuclei is reviewed. Calculations for the non-mesonic mode are discussed in some detail within the context of a model which describes the strangeness-changing, parity-violating, ΛN → NN ''transition potential'' in terms of π, rho, ω, eta, K, K*, and ''sigma'' exchanges. Results are presented for the total decay rate, the ratio of proton- to neutron-stimulated decay rates, and the as yet unmeasured ratio of parity-violating to parity-conserving decay rates. Calculations for nuclear matter, which are in reasonable agreement with experiment, suggest that these rates (particularly the two ratios) can provide important tests of the form of the transition potential. Considerations of finite hypernuclei are also discussed. Finally, other theoretical approaches and the present experimental situation are briefly summarized. 17 refs., 3 figs., 3 tabs

  18. Essence of hypernuclear physics

    International Nuclear Information System (INIS)

    Bando, H.

    1982-09-01

    This is a lecture on the present status of hypernuclear physics so that a gross picture can be obtained on what have been done and what should be done. The baryons with non-zero strangeness quantum number are generally called hyperons (hereafter denoted as Y), of which the lambda, sigma and xi particles together with the nucleon (N) constitute the baryon octet. A hypernucleus is the nuclear many-body system which contains hyperons in addition to nucleons as its constituent particles. The properties of the Y-N interaction can be extracted from the Y-N scattering data and information of hypernuclei along with theoretical consideration. The binding energy of a lambda particle in hypernuclei has been obtained from emulsion experiment. The hypernuclear excited states were observed in the (K - , pi - ) reaction experiment. The theoretical studies to understand the properties of the lambda single particle potential have been made within the framework of the G-matrix theory by employing Nijmegen OBE Y-N potential. The collective excitation of lambda hypernuclei is discussed. Spectroscopic information can be obtained by measuring the gamma-ray from hypernuclei. The sigma-hypernuclei have been observed through (K - , pi - ) reaction, while the experimental evidence of the xi-hypernuclei is not yet reported. The properties of both hypernuclei are discussed. The production and the properties of multi-hypernuclei are also discussed. The decay of lambda-hypernuclei will give structural characteristics of parents and daughters. Discussion of flavour nuclei and the concluding remarks are presented. (Kato, T.)

  19. Narrow Sigma -hypernuclear states

    CERN Document Server

    Gal, A

    1980-01-01

    It is shown that the spin-isospin dependence of low-energy Sigma N to Lambda N conversion leads to substantial quenching of nuclear-matter estimates of the widths of some Sigma -hypernuclear states produced in (K/sup -/, pi ) reactions, to a level below 10 MeV. The estimated widths compare favorably with those of the Sigma -hypernuclear peaks recently observed at CERN for /sup 7/Li, /sup 9/Be, and /sup 12/C. Tentative quantum number assignments are suggested for these states. (10 refs).

  20. Hypernuclear spectroscopy with the (e, e-prime K+) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Yu Fujii

    2003-06-16

    Experimental conditions of the (e,e'K+) reaction for hypernuclear spectroscopy at Jefferson Lab Hall C are considered. Then two hypernuclear experiments at Hall C, Jlab E89-009 and E01-011 are introduced and compared, and possibility to extract information on hypernuclear states are discussed by referring expected spectra obtained with a DWIA calculation.

  1. Open problems and future prospects for hypernuclear physics

    International Nuclear Information System (INIS)

    Dover, C.B.

    1992-01-01

    We appraise the current status of our knowledge of hypernuclear structure physics, and emphasize the unsolved problems. The prospects for significant advances in high resolution hypernuclear spectroscopy with CW electron beams at CEBAF or intense pion beams at the proposed PILAC facility at LPF are discussed. These facilities could greatly extend our understanding of strangeness S = -1 hypernuclear systems. For S = -2 systems, new events have been seen in a (K - ,K + ) hybrid counter-emulsion experiment at KEK in Japan. We give a theoretical interpretation of one of these events, as well as some further possibilities for the exploration of ΛΛ hypernuclear spectroscopy via Ξ - -atoms. We mention some possible enhancements of (K - ,K + ) or (K - ,K 0 ) cross sections to discrete states, due to ΞN-ΛΛ configuration mixing in a shell model description of S = -2 hypernuclei. Finally, we explore the possibilities for producing multi-strange nuclei or droplets of strange quark matter (''strangelets'') in relativistic heavy ion collisions

  2. Hypernuclear Spectroscopy at JLab Hall C

    International Nuclear Information System (INIS)

    Hashimoto, Osamu; Chiba, Atsushi; Doi, Daisuke; Fujii, Yu; Toshiyuki, Gogami; Kanda, Hiroki; Kaneta, M.; Kawama, Daisuke; Maeda, Kazushige; Maruta, Tomofumi; Matsumura, Akihiko; Nagao, Sho; Nakamura, Satoshi; Shichijo, Ayako; Tamura, Hirokazu; Taniya, Naotaka; Yamamoto, Taku; Yokota, Kosuke; Kato, S.; Sato, Yoshinori; Takahashi, Toshiyuki; Noumi, Hiroyuki; Motoba, T.; Hiyama, E.; Albayrak, Ibrahim; Ates, Ozgur; Chen, Chunhua; Christy, Michael; Keppel, Cynthia; Kohl, Karl; Li, Ya; Liyanage, Anusha Habarakada; Tang, Liguang; Walton, T.; Ye, Zhihong; Yuan, Lulin; Zhu, Lingyan; Baturin, Pavlo; Boeglin, Werner; Dhamija, Seema; Markowitz, Pete; Raue, Brian; Reinhold, Joerg; Hungerford, Ed; Ent, Rolf; Fenker, Howard; Gaskell, David; Horn, Tanja; Jones, Mark; Smith, Gregory; Vulcan, William; Wood, Stephen; Johnston, C.; Simicevic, Neven; Wells, Stephen; Samanta, Chhanda; Hu, Bitao; Shen, Ji; Wang, W.; Zhang, Xiaozhuo; Zhang, Yi; Feng, Jing; Fu, Y.; Zhou, Jian; Zhou, S.; Jiang, Yi; Lu, H.; Yan, Xinhu; Ye, Yunxiu; Gan, Liping; Ahmidouch, Abdellah; Danagoulian, Samuel; Gasparian, Ashot; Elaasar, Mostafa; Wesselmann, Frank; Asaturyan, Arshak; Margaryan, Amur; Mkrtchyan, Arthur; Mkrtchyan, Hamlet; Tadevosyan, Vardan; Androic, Darko; Furic, Miroslav; Petkovic, Tomislav; Seva, Tomislav; Niculescu, Gabriel; Niculescu, Maria-Ioana; Rodriguez, Victor; Cisbani, Evaristo; Cusanno, Francesco; Garibaldi, Franco; Urciuoli, Guido; De Leo, Raffaele; Maronne, S.; Achenbach, Carsten; Pochodzalla, J.

    2010-01-01

    Since the 1st generation experiment, E89-009, which was successfully carried out as a pilot experiment of (e,e(prime)K + ) hypernuclear spectroscopy at JLab Hall C in 2000, precision hypernuclear spectroscopy by the (e,e(prime)K + ) reactions made considerable progress. It has evolved to the 2nd generation experiment, E01-011, in which a newly constructed high resolution kaon spectrometer (HKS) was installed and the 'Tilt method' was adopted in order to suppress large electromagnetic background and to run with high luminosity. Preliminary high-resolution spectra of 7 ΛHe and 28 ΛAl together with that of 12 ΛB that achieved resolution better than 500 keV(FWHM) were obtained. The third generation experiment, E05-115, has completed data taking with an experimental setup combining a new splitter magnet, high resolution electron spectrometer (HES) and the HKS used in the 2nd generation experiment. The data were accumulated with targets of 7 Li, 9 Be, 10 B, 12 C and 52 Cr as well as with those of CH 2 and H 2 O for calibration. The analysis is under way with particular emphasis of determining precision absolute hypernuclear masses. In this article, hypernuclear spectroscopy program in the wide mass range at JLab Hall C that has undergone three generation is described.

  3. The alpha decay rates of heavy hypernuclei

    International Nuclear Information System (INIS)

    Thakkar, Kaushal; Majethiya, Ajay; Vinodkumar, P.C.

    2012-01-01

    Hypernuclear physics is of great interest because it stands at the intersection of nuclear physics, particle physics as well as astro physics. Hypernuclear physics has recently received lot of attention as large number of hypernuclei are produced and studied experimentally. Many future experimental facilities are also planned to study this field of strange matter. For example, the Hyperball collaboration developed an array of germanium detectors with fast electronics for hypernuclear spectroscopy. Details on the progress and scope of this field are available in recent review articles. Here, the paper makes an attempt to identify and study the decay tunneling probability and half life time of energetically allowed Λ - hypernuclei

  4. π0 decay branching ratios of 5ΛHe and 12ΛC hypernuclei

    International Nuclear Information System (INIS)

    Okada, S.; Ajimura, S.; Aoki, K.; Banu, A.; Bhang, H.C.; Fukuda, T.; Hashimoto, O.; Hwang, J.I.; Kameoka, S.; Kang, B.H.; Kim, E.H.; Kim, J.H.; Kim, M.J.; Maruta, T.; Miura, Y.; Miyake, Y.; Nagae, T.; Nakamura, M.; Nakamura, S.N.; Noumi, H.; Okayasu, Y.; Outa, H.; Park, H.; Saha, P.K.; Sato, Y.; Sekimoto, M.; Takahashi, T.; Tamura, H.; Tanida, K.; Toyoda, A.; Tsukada, K.; Watanabe, T.; Yim, H.J.

    2005-01-01

    We precisely measured π0 branching ratios of 5 Λ He and 12 Λ C hypernuclei produced via the (π+,K+) reaction. Using these π0 branching ratios with the π- branching ratios and lifetimes, we obtained the π0 decay widths and the non-mesonic weak decay widths with an accuracy of ∼5% (stat) for both hypernuclei

  5. Optimization of the target system for the hypernuclear experiment at anti PANDA

    Energy Technology Data Exchange (ETDEWEB)

    Bleser, Sebastian; Sanchez Lorente, Alicia; Steinen, Marcell [Helmholtz-Institut Mainz (Germany); Iazzi, Felice [Politecnico di Torino, Turin (Italy); INFN, Turin (Italy); Pochodzalla, Josef; Rittgen, Kai; Sahin, Cihan [Mainz Univ. (Germany). Inst. fuer Kernphysik; Collaboration: PANDA-Collaboration

    2013-07-01

    Gamma spectroscopy of double Λ hypernuclei will be one of the main topics addressed by the anti PANDA experiment at the planned FAIR-Facility at Darmstadt, Germany. For this project a dedicated hypernuclear detector setup will be installed. In addition to the general purpose of the anti PANDA detector it consists of a primary nuclear target for the production of Ξ{sup -}+ anti Ξ pairs, a secondary active target for the formation of hypernuclei and the identification of associated decay products as well as a germanium detector array to perform γ spectroscopy. In order to stop the Ξ{sup -} particles and track pions from the decay of the produced hypernuclei, the secondary target is composed as a compact structure of silicon microstrip detectors and absorber material. Results of the current hardware development will be presented on the poster including stability tests for the primary target chamber, the readout of silicon microstrip detectors with ultra-thin flexible cables to fan out the readout electronics and design studies of support structures for the whole detector setup. On the simulation side a compromise between the stopping of Ξ{sup -} hyperons and the reconstruction accuracy of weak decay pions is discussed.

  6. Asymmetry in nonmesonic decay of polarized sup 5 subLAMBDA He hypernucleus

    CERN Document Server

    Ajimura, S; Ejiri, H; Hasegawa, T; Hashimoto, O; Ishikawa, M; Ikeda, K; Kim, Y; Kishimoto, T; Maeda, K; Manabe, K; Nagae, T; Nakano, T; Noumi, H; Okusu, A; Park, H; Sekimoto, M; Shibata, T; Shinkai, N; Takahashi, T; Tanaka, Y; Youn, M

    2000-01-01

    We have measured the asymmetric emission of protons and pions from the non mesonic decay of the polarized sup 5 subLAMBDA He produced by the (pi sup + , K sup +) reaction. The polarization was derived by the observed asymmetry of the mesonic decay pions for the first time. The asymmetry parameter of the non mesonic decay has been evaluated using the obtained polarization and the asymmetry of the decay protons. The positive asymmetry parameter contradicts theoretical prediction based on meson exchange model. The discrepancy can be attributed to insufficient knowledge of the weak LAMBDA N interaction, especially at short range, which may consistently explain the discrepancy seen in the partial decay rates of the non mesonic decay.

  7. Observation of two non-mesonic decays in flight of hyperfragments

    International Nuclear Information System (INIS)

    Deka, G.C.; Deka, K.C.; Das, D.C.

    1989-01-01

    Elaborate studies of hyperfragments: their production mechanism, modes of decay, Λsup(0)-binding energy and mean-life have been made. During author s' recent investigation, two such events were detected, and were identified as due to the decay in flight of Li and B hyperfragments without emission of pi-mesons. Their mean-life could be estimated, and was found to be of the order of 10 -11 second against the normal mean-life of the order of 10 -11 second for Λsup(0)-hyperon. (author). 6 refs

  8. SPECTROSCOPY OF MEDIUM-MASS HYPERNUCLEAR PRODUCTION

    Czech Academy of Sciences Publication Activity Database

    Motoba, T.; Bydžovský, Petr; Sotona, Miloslav; Itonaga, K.; Ogawa, K.; Hashimoto, O.

    2010-01-01

    Roč. 19, č. 12 (2010), s. 2470-2479 ISSN 0218-3013. [Sendai International Conference on Strangeness in Nuclear and Hadronic Systems. Sendai, 15.12.2008-18.12.2008] Institutional research plan: CEZ:AV0Z10480505 Keywords : Hypernuclear photoproduction * DWIA * unnatural parity states Subject RIV: BE - Theoretical Physics Impact factor: 0.695, year: 2010

  9. Hypernuclear matter in strong magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Monika [Institute for Theoretical Physics, J.W. Goethe-University, D-60438 Frankfurt am Main (Germany); Indian Institute of Technology Rajasthan, Old Residency Road, Ratanada, Jodhpur 342011 (India); Mukhopadhyay, Banibrata [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Sedrakian, Armen, E-mail: sedrakian@th.physik.uni-frankfurt.de [Institute for Theoretical Physics, J.W. Goethe-University, D-60438 Frankfurt am Main (Germany)

    2013-01-17

    Compact stars with strong magnetic fields (magnetars) have been observationally determined to have surface magnetic fields of order of 10{sup 14}–10{sup 15} G, the implied internal field strength being several orders larger. We study the equation of state and composition of dense hypernuclear matter in strong magnetic fields in a range expected in the interiors of magnetars. Within the non-linear Boguta–Bodmer–Walecka model we find that the magnetic field has sizable influence on the properties of matter for central magnetic field B⩾10{sup 17} G, in particular the matter properties become anisotropic. Moreover, for the central fields B⩾10{sup 18} G, the magnetized hypernuclear matter shows instability, which is signalled by the negative sign of the derivative of the pressure parallel to the field with respect to the density, and leads to vanishing parallel pressure at the critical value B{sub cr}≃10{sup 19} G. This limits the range of admissible homogeneously distributed fields in magnetars to fields below the critical value B{sub cr}.

  10. Hypernuclear physics studies of the P̅ANDA experiment at FAIR

    Science.gov (United States)

    Sanchez Lorente, Alicia

    2015-05-01

    Hypernuclear research will be one of the main topics addressed by the PANDA experiment at the planned Facility for Antiproton and Ion Research FAIR at Darmstadt (Germany). [1, 2] Thanks to the use of stored p̅ beams, copious production of double Λ hypernuclei is expected at the PANDA experiment, which will enable high precision γ spectroscopy of such nuclei for the first time, and consequently a unique chance to explore the hyperon-hyperon interaction. In particular, ambiguities of past experiments in determining the strength of the ΛΛ interaction will be avoided thanks to the excellent energy precision of a few keV (FWHM) achieved by germanium detectors. Such a resolution capability is particularly needed to resolve the small energy spacing of the order of (10-100) keV, which is characteristic from the spin doublet in hypernuclei the so -called "hypernuclear fine structure". In comparison to previous experiments, PANDA will benefit from a novel technique to assign the various observable γ-transitions in a unique way to specific double hypernuclei by exploring various light targets. Nevertheless, the ability to carry out unique assignments requires a devoted hypernuclear detector setup. This consists of a primary nuclear target for the production of Ξ- + overline Xi pairs, a secondary active target for the hypernuclei formation and the identification of associated decay products and a germanium array detector to perform γ spectroscopy. Moreover, one of the most challenging issues of this project is the fact that all detector systems need to operate in the presence of a high magnetic field and a large hadronic background. Accordingly, the need of an innovative detector concept will require dramatic improvements to fulfil these conditions and that will likely lead to a new generation of detectors. In the present work details concerning the current status of the activities related to the detector developments for this challenging programme will be given. Among

  11. Cooling of hypernuclear compact stars

    Science.gov (United States)

    Raduta, Adriana R.; Sedrakian, Armen; Weber, Fridolin

    2018-04-01

    We study the thermal evolution of hypernuclear compact stars constructed from covariant density functional theory of hypernuclear matter and parametrizations which produce sequences of stars containing two-solar-mass objects. For the input in the simulations, we solve the Bardeen-Cooper-Schrieffer gap equations in the hyperonic sector and obtain the gaps in the spectra of Λ, Ξ0, and Ξ- hyperons. For the models with masses M/M⊙ ≥ 1.5 the neutrino cooling is dominated by hyperonic direct Urca processes in general. In the low-mass stars the (Λp) plus leptons channel is the dominant direct Urca process, whereas for more massive stars the purely hyperonic channels (Σ-Λ) and (Ξ-Λ) are dominant. Hyperonic pairing strongly suppresses the processes on Ξ-s and to a lesser degree on Λs. We find that intermediate-mass 1.5 ≤ M/M⊙ ≤ 1.8 models have surface temperatures which lie within the range inferred from thermally emitting neutron stars, if the hyperonic pairing is taken into account. Most massive models with M/M⊙ ≃ 2 may cool very fast via the direct Urca process through the (Λp) channel because they develop inner cores where the S-wave pairing of Λs and proton is absent.

  12. Hypernuclear physics studies of the PANDA experiment at FAIR

    Science.gov (United States)

    Sanchez Lorente, Alicia

    2014-09-01

    Hypernuclear research will be one of the main topics addressed by the PANDA experiment at the planned Facility for Antiproton and Ion Research FAIR at Darmstadt (Germany). http://www. gsi.de, http://www.gsi.de/fair/. Thanks to the use of stored overline {p} beams, copious production of double Λ hypernuclei is expected at the PANDA experiment, which will enable high precision γ spectroscopy of such nuclei for the first time, and consequently a unique chance to explore the hyperon-hyperon interaction. In particular, ambiguities of past experiments in determining the strength of the ΛΛ interaction will be avoided thanks to the excellent energy precision of a few keV (FWHM) achieved by germanium detectors. Such a resolution capability is particularly needed to resolve the small energy spacing of the order of (10-100) keV, which is characteristic from the spin doublet in hypernuclei the so -called "hypernuclear fine structure". In comparison to previous experiments, PANDA will benefit from a novel technique to assign the various observable γ-transitions in a unique way to specific double hypernuclei by exploring various light targets. Nevertheless, the ability to carry out unique assignments requires a devoted hypernuclear detector setup. This consists of a primary nuclear target for the production of {Ξ }-+overline {Ξ } pairs, a secondary active target for the hypernuclei formation and the identification of associated decay products and a germanium array detector to perform γ spectroscopy. Moreover, one of the most challenging issues of this project is the fact that all detector systems need to operate in the presence of a high magnetic field and a large hadronic background. Accordingly, the need of an innovative detector concept will require dramatic improvements to fulfil these conditions and that will likely lead to a new generation of detectors. In the present talk details concerning the current status of the activities related to the detector developments

  13. Optimization of the target system for the hypernuclear experiment at PANDA

    Energy Technology Data Exchange (ETDEWEB)

    Bleser, Sebastian; Sanchez Lorente, Alicia; Steinen, Marcell [Helmholtz-Institut Mainz (Germany); Iazzi, Felice [Politecnico, Torino (Italy); INFN, Torino (Italy); Pochodzalla, Josef; Rittgen, Kai; Sahin, Cihan [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, Mainz (Germany)

    2014-07-01

    Gamma spectroscopy of double Λ hypernuclei will be one of the main topics addressed by the PANDA experiment at the planned FAIR-facility at Darmstadt, Germany. For this project a dedicated hypernuclear detector setup will be installed. In addition to the general purpose of the PANDA detector it consists of a primary nuclear target for the production of Ξ{sup -} + anti Ξ pairs, a secondary active target for the formation of hypernuclei and the identification of associated decay products as well as a germanium detector array to perform γ spectroscopy. Results of the current hardware development will be presented in the talk: For the positioning of the primary filament target in the beam halo the functionality of piezo motors is investigated in vacuum. Stability tests of the primary target chamber are performed with various thin materials. For the secondary target the readout of silicon microstrip detectors with ultra-thin flexible cables is checked to fan out the readout electronics. Furthermore, design studies of support structures for the whole detector setup are considered. On the simulation side a compromise between the stopping probability of Ξ{sup -} hyperons and the reconstruction accuracy of weak decay pions is discussed.

  14. "Alpha decays" of Be-10(Lambda) and B-10(Lambda) hypernuclei on a nuclotron: A clue to some puzzles in nonleptonic processes

    Czech Academy of Sciences Publication Activity Database

    Batusov, Yu.; Lukstins, J.; Majling, Lubomír; Parfenov, AN.

    2005-01-01

    Roč. 36, č. 2 (2005), s. 169-190 ISSN 1063-7796 R&D Projects: GA ČR GA202/02/0930 Institutional research plan: CEZ:AV0Z10480505 Keywords : nonmesonic weak decay * hyperon-nucleon interaction * Lambda-N-interaction Subject RIV: BE - Theoretical Physics Impact factor: 0.505, year: 2005

  15. Hyperon and hypernuclear physics with intense beams

    International Nuclear Information System (INIS)

    Gibson, B.F.

    1983-01-01

    A brief examination of progress in the study of hypernuclear physics and the hyperon-nucleon interaction is presented. The use of #betta#-hypernuclei in the study of conventional (nonstrange) nuclei is explored. The status of the hyperon-nucleon force problem is reviewed. Anecdotal results are discussed for baryon numbers 4 and 13. μ-hypernuclei are discussed. Production of S = -2 hypernuclei is mentioned

  16. A study of the #Delta# I = 1/2 rule in the weak decay of S-shell hypernuclei: BNL E931

    International Nuclear Information System (INIS)

    Gill, R.L.

    2000-01-01

    It is empirically observed that the non-leptonic decay of strange hadrons is enhanced when the change in isospin is 1/2. This is generalized in the ''ΔI = 1/2 rule'' that states that all such decays proceed predominantly through ΔI = 1/2 amplitudes. However, there is no definitive explanation for this apparently universal rule. Non-mesonic decay of Λ-hypernuclei can occur through a weak decay process ΛN -> ηN. When stimulated by a neutron, two neutrons are emitted from the nucleus, and when stimulated by a proton, a proton and neutron are emitted. By measuring the relative decay widths (Γ n /Γ p ) in the full set of s-shell hypernuclei, a sensitive test of the ΔI = 1/2 rule, and the determination of its applicability to non-mesonic decays can be made. In addition, information about the spin-isospin dependence of the weak decay process can be extracted. A measurement of Γ n /Γ p , to an accuracy of even 50% will be sufficient to address important issues relating to the ΔI = 1/2 rule and to the weak decay process. The experiment will measure the ratio Γ n /Γ p , following the decay of 4 H which is produced by a stopped K - beam in a liquid Helium target. The Neutral Meson Spectrometer will be used to identify stopped kaon events by detection of the gamma rays that follow the decay of the emitted π 0 . Arrays of charged particle and neutron detectors will measure the relative neutron and proton emission probabilities. An engineering run was performed in 1998, without the Helium target, which demonstrated that the technique is feasible. The full experiment is scheduled at the Alternating Gradient Synchrotron for the spring 2001 running period

  17. Many-particle leptonic decays of hypernuclei

    International Nuclear Information System (INIS)

    Lyul'ka, V.A.

    1982-01-01

    Leptonic decays of light hypernuclei of the type /sup A/X/sub Λ/→/sup A/-1X+p+l - +nu-bar occurring with a fairly large energy release (compared to π - meson decays) are studied. The energy and angular distributions of the decay products are calculated taking into account the strong interaction in the final state in the p-/sup A/-1X system and also the Pauli principle. The study is carried out for different sets of the kinematic variables describing decays of this type. It is shown that the effect of the final-state interaction significantly determines the energy distributions of the interacting particles and weakly affects the analogous lepton distributions in decays of this type. It is shown that it is necessary to take this effect into account in analyzing other types of hypernuclear decays with a similar energy release, namely, mesonless decays

  18. Hypernuclear physics with a neutral meson spectrometer

    International Nuclear Information System (INIS)

    Peng, J.C.

    1993-01-01

    The (K - , π degrees) reaction, which complements the (K - , π - ) and the (π + , K + ) reactions, offers another means to study hypernuclear physics. The physics motivation for measuring the (K - , π degrees) reaction is discussed. The feasibility for detecting π degrees using the LAMPF Neutral Meson Spectrometer is studied with Monte-Carlo simulations. We conclude that the (K - , π degrees) reaction can be well measured at existing kaon beam lines

  19. Theoretical studies on the alpha α decay half-lives of hyper and normal isotopes of Po

    Science.gov (United States)

    Santhosh, K. P.; Nithya, C.

    2018-03-01

    The α decay half-lives of hyper and normal isotopes of Po nuclei are studied in the present work. The inclusion of Λ - N interaction changes the half-life for α decay. The theoretical predictions on the α decay half-lives of normal Po isotopes are compared with experimental results and are seen to be matching well with each other. The neutron shell closure at N = 126 is found to be the same for both normal and hypernuclei. The Geiger-Nuttal (G-N) law for α decay is unaltered in the case of hypernuclei. The hypernuclei will decay into normal nuclei by mesonic or non-mesonic decay modes. Since the half-lives of normal Po nuclei are well within the experimental limits, our theoretical results suggest experimental verification of the α emission from hyper Po nuclei in a cascade process.

  20. 1 to 2 GeV/c beam line for hypernuclear and kaon research

    International Nuclear Information System (INIS)

    Chrien, R.E.

    1985-01-01

    A kaon beam line operating in the range from 1.0 to 2.0 GeV/c is proposed. The line is meant for kaon and pion research in a region hitherto inaccessible to experimenters. Topics in hypernuclear and kaon physics of high current interest include the investigation of doubly strange nuclear systems with the K - ,K + reaction, searching for dibaryon resonances, hyperon-nucleon interactions, hypernuclear γ rays, and associated production of excited hypernuclei. The beam line would provide separated beams of momentum analyzed kaons at intensities greater than 10 6 particles per spill with a momentum determined to one part in a thousand. This intensity is an order of magnitude greater than that currently available. 63 references

  1. Exchange currents for hypernuclear magnetic moments

    International Nuclear Information System (INIS)

    Saito, K.; Oka, M.; Suzuki, T.

    1997-01-01

    The meson (K and π) exchange currents for the hypernuclear magnetic moments are calculated using the effective Lagrangian method. The seagull diagram, the mesonic diagram and the Σ 0 -excitation diagram are considered. The Λ-N exchange magnetic moments for 5 Λ He and A=6 hypernuclei are calculated employing the harmonic oscillator shell model. It is found that the two-body correction is about -9% of the single particle value for 5 Λ He. The π exchange current, induced only in the Σ 0 -excitation diagram, is found to give dominant contribution for the isovector magnetic moments of hypernuclei with A=6. (orig.)

  2. Search for $\\Sigma$ Hypernuclear States using the Strangeness Exchange Reactions $(K^{-},\\pi^{-})$ and $(K^{-},\\pi^{+})$

    CERN Multimedia

    2002-01-01

    In previous $\\Lambda$ hypernuclei experiments details of the $\\Lambda$ nucleus interaction have been deduced, the most outstanding being a very small spin orbit interaction in p$^{-}$ and sd shell $\\Lambda$ hypernuclei. This kind of information is decisive in the understanding of the baryon interaction and will contribute to distinguish between the boson exchange and the QCD motivated picture of the baryon baryon interaction. To further exploit the hyperon nucleus interaction one has to investigate hypernuclei with hyperons of different quark configuration, i.e. $\\Sigma$ hypernuclei. Since the $\\Sigma\\$ particle can, in contrast to the $\\Lambda$, decay by strong interaction in the nucleus, the existence of narrow states was not obvious. A small momentum transfer guarantees that the spectra are dominated by a few strong transitions to narrow hypernuclear states with the same spin and space quantum numbers as the target nucleus. Therefore a new kaon beamline was built with a lower momentum of 400~MeV/c and a co...

  3. Hypernuclear weak decay and the ΔI = 1/2 rule

    International Nuclear Information System (INIS)

    Barnes, P.D.

    1987-01-01

    Recent measurements of the weak decay of Λ hypernuclei are reported and discussed in the context of the weak hyperon-baryon effective Hamiltonian. The results are compared to predictions of both meson exchange and quark-quark weak interaction models. 14 refs., 4 figs., 2 tabs

  4. Hypernuclear properties derived from the Nijmegen soft-core OBE potential

    International Nuclear Information System (INIS)

    Yamamoto, Yasuo; Bando, Hiroharu.

    1990-01-01

    The Nijmegen soft-core YN potential is applied to the G-matrix calculation in nuclear matter, characteristics of which are investigated in comparison with the hard-core models D and F. The ΛN G-matrix interaction is simulated in a three-range Gaussian form and applied to various hypernuclear calculations. Λ binding energies in ground and excited states are wholly reproduced from light to medium heavy hypernuclei observed in experiments. (author)

  5. Investigation of high-precision Λ hypernuclear spectroscopy via the (e,e'K+) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Kawama, Daisuke [Tohoku Univ., Sendai (Japan)

    2011-01-01

    The study of Λ hypernuclear structure is very interesting in point of the understanding of the interaction between Λ and nucleon (Λ-N interaction) and its strange structure itself due to the containment of a Λ hyperon which has a strangeness as a new degree of freedom. In the several way to study the Lamda hypernuclei, the (e,e'K+) reaction spectroscopy is a powerful tool for the precise investigation of Λ hypernuclear structure. The purpose of the preset thesis is the establishment of the experimental design with the efficient data analysis method for the (e,e'K+) hypernuclear spectroscopic experiment in the wide mass region (from A=7 to A=52). It is very challenging to perform the (e,e'K+) spectroscopic experiment with such a heavy target, because of the huge electron background due to the bremsstrahlung process. In the experiment, it is required to obtain the necessary hypernuclear yield, suppressing the background event ratio. We achieved these requirements by newly constructing the high resolution electron spectrometer (HES) and splitter magnet (SPL) dedicated to the (e,e'K+) spectroscopic experiment. The HES consists of two quadrupole magnets and a dipole magnets (Q-Q-D) with a momentum resolution of dp/p = 3x10-4 at p = 0.84 GeV/c. It was used being vertically tilted by 6.5 degree so as to optimize signal to noise ratio and hypernuclear yield. The SPL is a dipole magnet. The experimental target was placed at the entrance of this magnet. The role of the SPL is to separate four kind of particles; scattered kaons, photons created by the bremsstrahlung, the post beam and scattered electrons. In addition, since the SPL is a part of the kaon and electron spectrometers. We designed the magnet shape carefully considering these points. The experiment was performed with 2.344 GeV/c electron beam from CEBAF at Jefferson Lab. The experimental setup consists of the HES, SPL and HKS (high momentum resolution kaon

  6. Proceedings of TRIUMF/KEK workshop on hypernuclear physics at KAON

    International Nuclear Information System (INIS)

    1989-07-01

    A workshop on 'Hypernuclear Physics at KAON' was held on June 17-18, 1989 at KEK. 18 participants from abroad and more than 30 domestic participants attended. Following the general reviews of pre-KAON status, active discussions of future possibilities with KAON were carried out. Fundamental questions which stimulate experimental efforts were raised and various new ambitious ideas for experimental possibilities were presented. The discussions assist design studies of the KAON beam lines and help to promote the field of KAON physics. This publication is the collection of the transparencies and memoranda of the presentations and discussions. (A.Y.)

  7. Update of High Resolution (e, e ' K+) Hypernuclear Spectroscopy at Jefferson Lab's Hall A

    Czech Academy of Sciences Publication Activity Database

    Cusanno, F.; Acha, A.; Bydžovský, Petr; Chang, C. C.; Cisbani, E.; de Jager, C.W.; De Leo, R.; Frullani, S.; Garibaldi, F.; Higinbotham, D. W.; Iodice, M.; LeRose, J. J.; Markowitz, P.; Marrone, S.; Sotona, Miloslav; Urciuoli, G.M.

    2010-01-01

    Roč. 835, 1-4 (2010), s. 129-135 ISSN 0375-9474. [10th International Conference on Hypernuclear and Strange Particle Physics. Tokai, 14.09.2009-18.09.2009] R&D Projects: GA ČR GA202/08/0984 Institutional research plan: CEZ:AV0Z10480505 Keywords : hypernuclei * electroproduction reactions * strangeness Subject RIV: BE - Theoretical Physics Impact factor: 1.986, year: 2010

  8. Lifetimes of #betta#'s and μ's and short-distance nuclear phenomena

    International Nuclear Information System (INIS)

    Kisslinger, L.S.

    1982-06-01

    It is shown that short distance phenomena and thus quark structure play vital roles in the theory of #betta# and μ decays in nuclei. A hybrid two-baryon-quark shell model is used to estimate the lifetimes for nonmesonic decays of #betta#'s and μ's in nuclear matter

  9. Hypernuclear properties derived from the Juelich hyperon-nucleon interaction (in comparison with the Nijmegen interactions)

    International Nuclear Information System (INIS)

    Yamamoto, Y.; Reuber, A.; Himeno, H.; Nagata, S.; Motoba, T.

    1992-01-01

    The G-matrix interactions are derived from the Juelich YN interaction models A and B, compared with those from the Nijmegen models. The DDHF calculations for heavy Λ hypernuclei and the shell-model analysis for spin-doublet states of light hypernuclei are performed by use of the G-matrix interactions. It is demonstrated that the OBE models can be tested by the hypernuclear calculations. (author) 3 tabs., 5 figs., 23 refs

  10. Hypernuclear spectroscopy via (e,e'K+) in JLab's Hall A

    International Nuclear Information System (INIS)

    LeRose, John J.; Jager, C.W. de; Feuerbach, R.J.; Higinbotham, D.W.; Reitz, B.; Acha, A.; Markowitz, P.; Bydzovsky, P.; Sotona, M.; Chang, C.C.; Cisbani, E.; Cusanno, F.; Frullani, S.; Garibaldi, F.; De Leo, R.; Lagamba, L.; Marrone, S.; Iodice, M.; Urciuoli, G.M.

    2008-01-01

    Results are presented from a new experiment (E94-107) in Hall A of the Thomas Jefferson National Accelerator Facility (JLab) producing 12 Λ B, 16 Λ N, and 9 Λ Li using electroproduction, (e,e ' K + ). In the hypernuclear missing-mass spectrum the experiment achieves very good energy resolution (670 keV FWHM) by exploiting the characteristics of the High Resolution spectrometer pair and the exceptional beam quality available at JLab. The spectrometers were used with the addition of an INFN provided pair of septum magnets to reach the desired small angles. Also, the Hall A standard complement of equipment was further augmented by the addition of a Ring Imaging Cherenkov detector (RICH) to achieve the best possible kaon identification

  11. Experiments in intermediate energy physics

    International Nuclear Information System (INIS)

    Dehnhard, D.

    2003-01-01

    Research in experimental nuclear physics was done from 1979 to 2002 primarily at intermediate energy facilities that provide pion, proton, and kaon beams. Particularly successful has been the work at the Los Alamos Meson Physics Facility (LAMPF) on unraveling the neutron and proton contributions to nuclear ground state and transition densities. This work was done on a wide variety of nuclei and with great detail on the carbon, oxygen, and helium isotopes. Some of the investigations involved the use of polarized targets which allowed the extraction of information on the spin-dependent part of the triangle-nucleon interaction. At the Indiana University Cyclotron Facility (IUCF) we studied proton-induced charge exchange reactions with results of importance to astrophysics and the nuclear few-body problem. During the first few years, the analysis of heavy-ion nucleus scattering data that had been taken prior to 1979 was completed. During the last few years we created hypernuclei by use of a kaon beam at Brookhaven National Laboratory (BNL) and an electron beam at Jefferson Laboratory (JLab). The data taken at BNL for a study of the non-mesonic weak decay of the A particle in a nucleus are still under analysis by our collaborators. The work at JLab resulted in the best resolution hypernuclear spectra measured thus far with magnetic spectrometers

  12. Experiments in intermediate energy physics

    Energy Technology Data Exchange (ETDEWEB)

    Dehnhard, D.

    2003-02-28

    Research in experimental nuclear physics was done from 1979 to 2002 primarily at intermediate energy facilities that provide pion, proton, and kaon beams. Particularly successful has been the work at the Los Alamos Meson Physics Facility (LAMPF) on unraveling the neutron and proton contributions to nuclear ground state and transition densities. This work was done on a wide variety of nuclei and with great detail on the carbon, oxygen, and helium isotopes. Some of the investigations involved the use of polarized targets which allowed the extraction of information on the spin-dependent part of the triangle-nucleon interaction. At the Indiana University Cyclotron Facility (IUCF) we studied proton-induced charge exchange reactions with results of importance to astrophysics and the nuclear few-body problem. During the first few years, the analysis of heavy-ion nucleus scattering data that had been taken prior to 1979 was completed. During the last few years we created hypernuclei by use of a kaon beam at Brookhaven National Laboratory (BNL) and an electron beam at Jefferson Laboratory (JLab). The data taken at BNL for a study of the non-mesonic weak decay of the A particle in a nucleus are still under analysis by our collaborators. The work at JLab resulted in the best resolution hypernuclear spectra measured thus far with magnetic spectrometers.

  13. High resolution hypernuclear spectroscopy at Jefferson Lab Hall A

    International Nuclear Information System (INIS)

    Garibaldi, F.; Bydžovský, P.; Cisbani, E.; Cusanno, F.; De Leo, R.; Frullani, S.; Iodice, M.; LeRose, J.J.; Markowitz, P.; Millener, D.J.; Urciuoli, G.M.

    2013-01-01

    The characteristics of the Jefferson Lab electron beam, together with those of the experimental equipment, offer a unique opportunity to study hypernuclear spectroscopy via electromagnetic induced (e,e ′ K + ) reactions. Experiment 94-107 started a systematic study on 1p-shell targets, 12 C, 9 Be and 16 O. For 12 C for the first time measurable strength in the core-excited part of the spectrum between the ground state and the p state was shown in the 12 Λ B spectrum. For 16 O a high-quality 16 Λ N spectrum was produced for the first time with sub-MeV energy resolution. A very precise Λ binding energy value for 16 Λ N, calibrated against the elementary (e,e ′ K + ) reaction on hydrogen, has also been obtained. Preliminary data on the 9 Λ Li spectrum shows some disagreement in strength for the second and third doublet with respect to the theory

  14. Next-to-leading order effective field theory Lambda N -> NN potential in coordinate space

    Czech Academy of Sciences Publication Activity Database

    Peréz-Obiol Castaneda, Axel; Entem, D. R.; Julia-Diaz, B.; Parreno, A.

    2016-01-01

    Roč. 954, OCT (2016), s. 213-241 ISSN 0375-9474 R&D Projects: GA ČR(CZ) GA15-04301S Institutional support: RVO:61389005 Keywords : non-mesonic weak decay * effective field theory * hypernuclei Subject RIV: BE - Theoretical Physics Impact factor: 1.916, year: 2016

  15. Hypernuclear physics: A brief past and bright future

    International Nuclear Information System (INIS)

    Gibson, B.F.

    2000-01-01

    A primary reason for investigating the structure and reactions of baryon systems is to achieve an understanding the fundamental baryon-baryon force in the realm of non-perturbative QCD. Few-baryon systems play an essential role, because one can calculate complete solutions to test a particular baryon-baryon interaction ansatz. Hypernuclei, exotic nuclei containing one or more hyperons (Y = Λ, Σ, or Ξ) are crucial to this investigation, because they permit one to probe models based upon our experience in the nonstrange sector; they lie outside of the conventional world where our models were developed. That is, we can test whether our sophisticated models of the nucleon-nucleon (NN) interaction extrapolate successfully beyond the zero strangeness region in which the parameters were determined, or whether the models merely interpolate. The presence of the strangeness degree of freedom (flavor) adds a new dimension to our evolving picture of nuclear physics. We shall see that the physics of hypernuclei is both novel and puzzling, stretching our intuition and analysis capability beyond that developed during the more than half century that we have explored conventional nuclear physics. The hypernuclear sector of hadronic physics is not just a simple extension of zero-strangeness phenomena

  16. Experimental medium energy physics

    International Nuclear Information System (INIS)

    Barnes, P.D.

    1991-01-01

    This report discusses the following topics: Search for the H Dibaryon at the AGS; Hypernuclear Weak Decay Studies at the AGS; Relativistic Proton-Nucleus and Heavy Ion-Nucleus Collisions at the SPS; Hyperon-Antihyperon Production studies at LEAR; Hyperon Photoproduction at CEBAF; Double Lambda Hypernuclei; Weak Decay of Light Hypernuclei; and π 0 /γDetection with the CMU Scintillator Arrays

  17. Direct measurements of the lifetime of medium-heavy hypernuclei

    Science.gov (United States)

    Qiu, X.; Tang, L.; Chen, C.; Margaryan, A.; Wood, S. A.; Achenbach, P.; Ahmidouch, A.; Albayrak, I.; Androic, D.; Asaturyan, A.; Asaturyan, R.; Ates, O.; Badui, R.; Baturin, P.; Boeglin, W.; Bono, J.; Brash, E.; Carter, P.; Chen, X.; Chiba, A.; Christy, M. E.; Dalton, M. M.; Danagoulian, S.; De Leo, R.; Doi, D.; Elaasar, M.; Ent, R.; Fenker, H.; Fujii, Y.; Furic, M.; Gabrielyan, M.; Gan, L.; Garibaldi, F.; Gaskell, D.; Gasparian, A.; Gogami, T.; Hashimoto, O.; Horn, T.; Hu, B.; Hungerford, Ed V.; Jones, M.; Kanda, H.; Kaneta, M.; Kawama, D.; Khanal, H.; Kohl, M.; Liyanage, A.; Luo, W.; Maeda, K.; Markowitz, P.; Marikyan, G.; Maruta, T.; Matsumura, A.; Maxwell, V.; Mkrtchyan, A.; Mkrtchyan, H.; Nagao, S.; Nakamura, S. N.; Narayan, A.; Neville, C.; Niculescu, G.; Niculescu, M. I.; Nunez, A.; Nuruzzaman; Okayasu, Y.; Petkovic, T.; Pochodzalla, J.; Reinhold, J.; Rodriguez, V. M.; Samanta, C.; Sawatzky, B.; Seva, T.; Shichijo, A.; Tadevosyan, V.; Taniya, N.; Tsukada, K.; Veilleux, M.; Vulcan, W.; Wesselmann, F. R.; Yamamoto, T.; Ye, Z.; Yokota, K.; Yuan, L.; Zhamkochyan, S.; Zhu, L.; HKS (JLab E02-017) Collaboration

    2018-05-01

    The lifetime of a Λ particle embedded in a nucleus (hypernucleus) decreases from that of free Λ decay mainly due to the opening of the ΛN → NN weak decay channel. However, it is generally believed that the lifetime of a hypernucleus attains a constant value (saturation) for medium to heavy hypernuclear masses, yet this hypothesis has been difficult to verify. This paper presents a direct measurement of the lifetime of medium-heavy hypernuclei that were hyper-fragments produced by fission or break-up from heavy hypernuclei initially produced with a 2.34 GeV photon-beam incident on thin Fe, Cu, Ag, and Bi target foils. For each event, fragments were detected in coincident pairs by a low-pressure multi-wire proportional chamber system. The lifetime was extracted from decay time spectrum formed by the difference of the time zeros between the pairs. The measured lifetime from each target is actually a statistical average over a range of mass with mean about 1/2 of the target mass and appears to be a constant of about 200 ps. Although this result cannot exclude unexpected shorter or longer lifetimes for some specific hypernuclei or hypernuclear states, it shows that a systematic decrease in lifetime as hypernuclear mass increases is not a general feature for hypernuclei with mean mass up to A ≈ 130. On the other hand, the success of this experiment and its technique shows that the time delayed fissions observed and used by all the lifetime measurements done so far on heavy hypernuclei could likely have originated from hyper-fragments lighter than the assumed masses.

  18. Experimental medium energy physics

    International Nuclear Information System (INIS)

    Barnes, P.D.

    1990-01-01

    This report discusses the following topics: search for the H-dibaryon at the AGS; weak interaction studies with hypernuclear decays at the AGS; search for the ξ(2230) at LEAR; relativistic proton-nucleus and heavy ion-nucleus collisions at the SPS; hyperon-antihyperon production studies at LEAR; photoproduction of strange CEBAF; and experiment design development

  19. Hyperon compound nucleus

    International Nuclear Information System (INIS)

    Yamazaki, Toshimitsu.

    1987-11-01

    The formation of various hypernuclei from K - absorption at rest is discussed from the viewpoints of compound decay of highly excited hypernuclei in contrast to the direct reaction mechanism. Recent (stopped K - , π) experiments at KEK as well as old data of emulsion and bubble chamber experiments are discussed. Some future direction of hypernuclear spectroscopy is suggested. (author)

  20. Overview of strangeness nuclear physics

    International Nuclear Information System (INIS)

    Gibson, B.F.

    1998-01-01

    Novel as well as puzzling aspects of strangeness (S = -1 and S = -2) nuclear physics are highlighted. Opportunities to gain new insights into hypernuclear spectroscopy, structure, and weak decays and to contribute to the continuing effort to understand the fundamental baryon-baryon force are outlined. Connections to strangeness in heavy-ion reactions and astrophysics are noted

  1. Dirac phenomenology and hyperon-nucleus interactions

    Energy Technology Data Exchange (ETDEWEB)

    Mares, J; Jennings, B K [TRIUMF, Vancouver, British Columbia (Canada); Cooper, E D [Fraser Valley Univ. College, Chilliwack, British Columbia (Canada). Dept. of Physics

    1993-05-01

    We discuss various aspects of hyperon-nucleus interactions in the relativistic mean field theory. First, characteristics of {Lambda}, {Sigma} and {identical_to} hypernuclei, as well as multi strange baryonic objects, are investigated. The spin-orbit splittings and magnetic moments are shown to be very sensitive to the value of the tensor coupling f{omega}y. Second, optical potentials for {Lambda} and {Sigma} scattering off nuclei are developed based on a global nucleon-nucleon Dirac optical potential and SU(3) symmetry. The tensor coupling has a large effect on the predictions for the analyzing power. Third, the Dirac approach is used in the calculations of the non-mesonic decay of {Lambda} hypernuclei. The large discrepancy between the decay rates and data suggests the need for additional meson exchanges. (authors). 62 refs.,7 figs., 6 tabs.

  2. Strange quarks in nuclei

    International Nuclear Information System (INIS)

    Dover, C.B.

    1991-06-01

    We survey the field of strange particle nuclear physics, starting with the spectroscopy of strangeness S = -1 Λ hypernuclei, proceeding to an interpretation of recent data on S = -2 ΛΛ hypernuclear production and decay, and finishing with some speculations on the production of multi-strange nuclear composites (hypernuclei or ''strangelets'') in relativistic heavy ion collisions. 41 refs., 5 figs

  3. Hypernuclear production cross section in the reaction of 6Li + 12C at 2A GeV

    Directory of Open Access Journals (Sweden)

    C. Rappold

    2015-07-01

    Full Text Available Hypernuclear production cross sections have been deduced for the first time with induced reaction of heavy ion beam on fixed target and by means of the invariant mass method by the HypHI Collaboration exploiting the reaction of 6Li + 12C at 2A GeV or sNN=2.70 GeV. A production cross section of 3.9±1.4 μb for 3ΛH and of 3.1±1.0 μb for 4ΛH respectively in the projectile rapidity region was inferred as well as the total production cross section of the Λ hyperon was measured and found to be equal to 1.7±0.8 mb. A global fit based on a Bayesian approach was performed in order to include and propagate statistical and systematic uncertainties. Production ratios of 3ΛH/4ΛH, 3ΛH/Λ and 4ΛH/Λ were included in the inference procedure. The strangeness population factors S3 and S4 of 3ΛH and 4ΛH respectively were extracted. In addition, the multiplicities of the Λ hyperon, 3ΛH, and 4ΛH together with the rapidity and transversal momentum density distributions of the observed hypernuclei were extracted and reported.

  4. Experimental overview and challenge in strangeness nuclear physics — strangeness in the past and coming decades

    International Nuclear Information System (INIS)

    Imai, Kenichi

    2010-01-01

    A great progress has been made in strangeness nuclear physics in the past decade. Examples are; 1) The "hyperfine" structure of hypernuclei were measured with the Hyperball, and ΛN spin dependent interactions in p-shell hypernuclei were determined. 2) The "complete measurements" of the weak decay of hypernuclei were made and the np ratio puzzle in the non-mesonic decay was solved. 3) The discovery of a clean event of "Lambpha" and determination of its binding energy concluded that the Λ-Λ interaction is weak attractive. However, we still have important questions to be answered in this field, especially in relation with QCD and nuclear physics. For the future strangeness nuclear physics, we have and will have facilities such as JLab, SPring-8, Daphne, J-PARC, FAIR. We discuss experimental challenges in the strangeness nuclear physics and related fields in the next decade. (author)

  5. Experimental Medium Energy Physics

    International Nuclear Information System (INIS)

    1992-01-01

    This report discusses the following topics: Search for the H Dibaryon at the AGS; hypernuclear weak decay studies at the LAGS; search for strangelets using the 2 GeV/c beam line; experiment to detect double lambda hypernuclei; hyperon photoproduction at CEBAF; the region 1 drift chambers for the CLAS spectrometer; parity violating electron scattering from the proton: the G 0 experiment at CEBAF; and relativistic heavy ion - nucleus collisions at the SPS

  6. High precision γ spectroscopy of ΛΛ-Hypernuclei at the PANDA experiment

    International Nuclear Information System (INIS)

    Sanchez Lorente, A

    2013-01-01

    Hypernuclear research will be one of the main topics addressed by the PANDA experiment at FAIR at Darmstadt (Germany). Thanks to the use of stored antiproton beams, copious production of double ΛΛ-Hypernuclei is expected at the PANDA experiment, which will enable high precision gamma spectroscopy of such nuclei for the first time. At PANDA excited states of hypernuclei will be used as a starting point for the formation of double ΛΛ-Hypernuclei. In order to predict the yield of particle-stable double hypernuclei a microcanonical decay model was developed. For the detection of these nuclei, a devoted hypernuclear detector setup is planned. This set-up consists, in addition to the general purpose of the PANDA set-up, of a primary nuclear target for the production of pairs, a secondary active target for the hypernuclei formation and the identification of associated decay products and a germanium array detector to perform gamma spectroscopy. Moreover, one of the most challenging issues of this project is the fact that all detector systems need to operate in the presence of a high magnetic field and a large hadronic background. In these proceedings details concerning the identification procedure of double hypernuclei and the suppression of background will be presented. In addition, the current status of the activities related to the detector developments for this challenging programme will be briefly given.

  7. Double {Lambda}-hypernuclei at the PANDA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Lorente, Alicia, E-mail: a.sanchez@gsi.de [Helmholtz Institut Mainz (Germany); Collaboration: P-bar ANDA Collaboration

    2012-12-15

    Hypernuclear research will be one of the main topics addressed by the PANDA experiment at the planned Facility for Antiproton and Ion Research FAIR at Darmstadt (Germany). Thanks to the use of stored p-bar beams, copious production of double {Lambda} hypernuclei is expected at the PANDA experiment, which will enable high precision {gamma} spectroscopy of such nuclei for the first time. At PANDA excited states of {Xi}{sup }- hypernuclei will be used as a starting point for the formation of double {Lambda} hypernuclei. In order to predict the yield of particle stable double hypernuclei a microcanonical decay model was developed. For the detection of these nuclei, a devoted hypernuclear detector setup is planned. This set-up consists, in addition to the general purpose of the PANDA set-up, of a primary nuclear target for the production of {Xi}{sup -} + {Xi}-bar pairs, a secondary active target for the hypernuclei formation and the identification of associated decay products and a germanium array detector to perform {gamma} spectroscopy. Furthermore, the presence of {Xi}-bar can be used as an alternative to tag the strangeness in the {Xi}{sup -} + {Xi}-bar. All systems need to operate in the presence of a high magnetic field and a large hadronic background. In the present talk details concerning simulations, the identification procedure of double hypernuclei and the suppression of background will be presented. In addition, the present status of the detector developments for this programme will be briefly given.

  8. Study of hypernuclei fission

    International Nuclear Information System (INIS)

    Malek, F.

    1990-01-01

    This work is about PS177 experience made on LEAR machine at CERN in 1988. The annihilation reaction of anti protons on a target of Bismuth or Uranium is studied. Lambda particles are produced by this reaction, in the nucleus in 2% of cases 7.1 10 -3 hypernuclei by stopped antiproton in the target are produced. The prompt hypernucleus fission probability of uranium is 75% and that of Bismuth 10%. The mass distribution of fission fragments is symmetrical ((≡ the excitation energy of the nucleus is very high). If the nucleus hasn't fissioned, the non-mesonic lambda decay, gives it an energy of 100 MeV, what allows to fission later. This fission is delayed because the hypernucleus lifetime is 1.3 +0.25 -0.21 10 -10 sec for Bismuth [fr

  9. Neutron decay, semileptonic hyperon decay and the Cabibbo model

    International Nuclear Information System (INIS)

    Siebert, H.W.

    1989-01-01

    The decay rates and formfactor ratios of neutron decay and semileptonic hyperon decays are compared in the framework of the Cabibbo model. The results indicate SU(3) symmetry breaking. The Kobayashi-Maskawa matrix element V us determined from these decays is in good agreement with the value determined from K→πeν decays, and with unitarity of the KM-matrix. (orig.)

  10. Weak decays of doubly heavy baryons. Multi-body decay channels

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yu-Ji; Wang, Wei; Xing, Ye; Xu, Ji [Shanghai Jiao Tong University, INPAC, Shanghai Key Laboratory for Particle Physics and Cosmology, MOE Key Laboratory for Particle Physics, Astrophysics and Cosmology, School of Physics and Astronomy, Shanghai (China)

    2018-01-15

    The newly-discovered Ξ{sub cc}{sup ++} decays into the Λ{sub c}{sup +}K{sup -}π{sup +}π{sup +}, but the experimental data has indicated that this decay is not saturated by any two-body intermediate state. In this work, we analyze the multi-body weak decays of doubly heavy baryons Ξ{sub cc}, Ω{sub cc}, Ξ{sub bc}, Ω{sub bc}, Ξ{sub bb} and Ω{sub bb}, in particular the three-body nonleptonic decays and four-body semileptonic decays. We classify various decay modes according to the quark-level transitions and present an estimate of the typical branching fractions for a few golden decay channels. Decay amplitudes are then parametrized in terms of a few SU(3) irreducible amplitudes. With these amplitudes, we find a number of relations for decay widths, which can be examined in future. (orig.)

  11. Weak decays

    International Nuclear Information System (INIS)

    Wojcicki, S.

    1978-11-01

    Lectures are given on weak decays from a phenomenological point of view, emphasizing new results and ideas and the relation of recent results to the new standard theoretical model. The general framework within which the weak decay is viewed and relevant fundamental questions, weak decays of noncharmed hadrons, decays of muons and the tau, and the decays of charmed particles are covered. Limitation is made to the discussion of those topics that either have received recent experimental attention or are relevant to the new physics. (JFP) 178 references

  12. Classification of decays involving variable decay chains with convolutional architectures

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    Vidyo contribution We present a technique to perform classification of decays that exhibit decay chains involving a variable number of particles, which include a broad class of $B$ meson decays sensitive to new physics. The utility of such decays as a probe of the Standard Model is dependent upon accurate determination of the decay rate, which is challenged by the combinatorial background arising in high-multiplicity decay modes. In our model, each particle in the decay event is represented as a fixed-dimensional vector of feature attributes, forming an $n \\times k$ representation of the event, where $n$ is the number of particles in the event and $k$ is the dimensionality of the feature vector. A convolutional architecture is used to capture dependencies between the embedded particle representations and perform the final classification. The proposed model performs outperforms standard machine learning approaches based on Monte Carlo studies across a range of variable final-state decays with the Belle II det...

  13. Lifetime of heavy hypernuclei and its implications on the weak LAMBDA N interaction

    CERN Document Server

    Cassing, W; Kamys, B; Kulessa, P; Niewodniczanski, H; Ohm, H; Pysz, K; Rudy, Z; Schult, O W B; Ströher, H

    2003-01-01

    The lifetime of the LAMBDA-hyperon in heavy hypernuclei measured in proton-Au, -Bi and -U collisions by the COSY-13 Collaboration at COSY-Juelich has been analyzed to yield tau subLAMBDA=(145+-11) ps. This value for tau subLAMBDA is compatible with the lifetime extracted from antiproton annihilation on Bi and U targets, albeit much more accurate. Theoretical models based on the meson exchange picture and assuming the validity of the phenomenological DELTA I=1/2 rule predict the lifetime of heavy hypernuclei to be significantly larger (2-3 standard deviations). Such large differences indicate that at least one of the assumptions in these models is not fulfilled. A much better reproduction of the lifetimes of heavy hypernuclei is achieved in the phase space model, if the DELTA I=1/2 rule is discarded in the nonmesonic LAMBDA decay. (orig.)

  14. Lifetime of heavy hypernuclei and its implications on the weak ΛN interaction

    International Nuclear Information System (INIS)

    Cassing, W.; Jarczyk, L.; Kamys, B.; Kulessa, P.; Pysz, K.; Ohm, H.; Schult, O.W.B.; Stroeher, H.; Rudy, Z.

    2003-01-01

    The lifetime of the Λ-hyperon in heavy hypernuclei measured in proton-Au, -Bi and -U collisions by the COSY-13 Collaboration at COSY-Juelich has been analyzed to yield τ Λ =(145±11) ps. This value for τ Λ is compatible with the lifetime extracted from antiproton annihilation on Bi and U targets, albeit much more accurate. Theoretical models based on the meson exchange picture and assuming the validity of the phenomenological ΔI=1/2 rule predict the lifetime of heavy hypernuclei to be significantly larger (2-3 standard deviations). Such large differences indicate that at least one of the assumptions in these models is not fulfilled. A much better reproduction of the lifetimes of heavy hypernuclei is achieved in the phase space model, if the ΔI=1/2 rule is discarded in the nonmesonic Λ decay. (orig.)

  15. The identification of a cascade hypernucleus

    CERN Document Server

    Mondal, A S; Husain, A; Kasim, M M

    1979-01-01

    In a systematic search for rare hypernuclear species in nuclear emulsion exposed to 3.0 GeV/c K/sup -/-mesons at the CERN PS, an event with three connecting stars has been observed. The two secondary stars are most probably due to the decay of a cascade hypernucleus according to the following channel: /sub Xi //sup -13/-C to /sub Lambda //sup 8 /Be+/sub Lambda //sup 5/He+Q. The binding energy of the Xi - hypernucleus is B/sub Xi /-(/sub Xi //sup 13/-C)=(18.1+or-3.2) MeV. (11 refs).

  16. Proton decay theory

    International Nuclear Information System (INIS)

    Marciano, W.J.

    1983-01-01

    Topics include minimal SU(5) predictions, gauge boson mediated proton decay, uncertainties in tau/sub p/, Higgs scalar effects, proton decay via Higgs scalars, supersymmetric SU(5), dimension 5 operators and proton decay, and Higgs scalars and proton decay

  17. β-decay properties in the Cs decay chain

    Science.gov (United States)

    Benzoni, G.; Lică, R.; Borge, M. J. G.; Fraile, L. M.; IDS Collaboration

    2018-02-01

    The study of the decay of neutron-rich Cs isotopes has two main objectives: on one side β decay is a perfect tool to access the low-spin structures in the daughter Ba nuclei, where the evolution of octupole deformed shapes can be followed, while, on the other hand, the study of the gross properties of these decays, in terms of decay rates and branching to delayed-neutron emission, are fundamental inputs for the modelling of the r-process in the Rare-Earth Elements peak. Results obtained at CERN-ISOLDE are discussed within this framework and compared to existing data and predictions from state-of-the-art nuclear models.

  18. JENDL FP decay data file 2000 and the beta-decay theory

    International Nuclear Information System (INIS)

    Yoshida, Tadashi; Katakura, Jun Ichi; Tachibana, Takahiro

    2002-01-01

    JENDL FP Decay Data File 2000 has been developed as one of the special purpose files of the Japanese Evaluated Nuclear Data Library (JENDL), which constitutes a versatile nuclear data basis for science and technology. In the format of ENDF-6 this file includes the decay data for 1087 unstable fission product (FP) nuclides and 142 stable nuclides as their daughters. The primary purpose of this file is to use in the summation calculation of FP decay heat, which plays a critical role in nuclear safety analysis; the loss-of-coolant accident analysis of reactors, for example. The data for a given nuclide are its decay modes, the Q value, the branching ratios, the average energies released in the form of beta- and gamma-rays per decay, and their spectral data. The primary source of the decay data adopted here is the ENSDF (Evaluated Nuclear Structure Data File). The data in ENSDF, however, cover only the measured values. The data of the short-lived nuclides, which are essential for the decay heat calculations at short cooling times, are often fully lacking or incomplete even if they exist. This is mainly because of their short half-life nature. For such nuclides a theoretical model calculation is applied in order to fill the gaps between the true and the experimentally known decay schemes. In practice we have to predict the average decay energies and the spectral data for a lot of short-lived FPs by use of beta-decay theories. Thus the beta-decay theory plays a very important role in generating the FP decay data file

  19. In-trap decay spectroscopy for {beta}{beta} decays

    Energy Technology Data Exchange (ETDEWEB)

    Brunner, Thomas

    2011-01-18

    The presented work describes the implementation of a new technique to measure electron-capture (EC) branching ratios (BRs) of intermediate nuclei in {beta}{beta} decays. This technique has been developed at TRIUMF in Vancouver, Canada. It facilitates one of TRIUMF's Ion Traps for Atomic and Nuclear science (TITAN), the Electron Beam Ion Trap (EBIT) that is used as a spectroscopy Penning trap. Radioactive ions, produced at the radioactive isotope facility ISAC, are injected and stored in the spectroscopy Penning trap while their decays are observed. A key feature of this technique is the use of a strong magnetic field, required for trapping. It radially confines electrons from {beta} decays along the trap axis while X-rays, following an EC, are emitted isotropically. This provides spatial separation of X-ray and {beta} detection with almost no {beta}-induced background at the X-ray detector, allowing weak EC branches to be measured. Furthermore, the combination of several traps allows one to isobarically clean the sample prior to the in-trap decay spectroscopy measurement. This technique has been developed to measure ECBRs of transition nuclei in {beta}{beta} decays. Detailed knowledge of these electron capture branches is crucial for a better understanding of the underlying nuclear physics in {beta}{beta} decays. These branches are typically of the order of 10{sup -5} and therefore difficult to measure. Conventional measurements suffer from isobaric contamination and a dominating {beta} background at theX-ray detector. Additionally, X-rays are attenuated by the material where the radioactive sample is implanted. To overcome these limitations, the technique of in-trap decay spectroscopy has been developed. In this work, the EBIT was connected to the TITAN beam line and has been commissioned. Using the developed beam diagnostics, ions were injected into the Penning trap and systematic studies on injection and storage optimization were performed. Furthermore, Ge

  20. In-trap decay spectroscopy for ββ decays

    International Nuclear Information System (INIS)

    Brunner, Thomas

    2011-01-01

    The presented work describes the implementation of a new technique to measure electron-capture (EC) branching ratios (BRs) of intermediate nuclei in ββ decays. This technique has been developed at TRIUMF in Vancouver, Canada. It facilitates one of TRIUMF's Ion Traps for Atomic and Nuclear science (TITAN), the Electron Beam Ion Trap (EBIT) that is used as a spectroscopy Penning trap. Radioactive ions, produced at the radioactive isotope facility ISAC, are injected and stored in the spectroscopy Penning trap while their decays are observed. A key feature of this technique is the use of a strong magnetic field, required for trapping. It radially confines electrons from β decays along the trap axis while X-rays, following an EC, are emitted isotropically. This provides spatial separation of X-ray and β detection with almost no β-induced background at the X-ray detector, allowing weak EC branches to be measured. Furthermore, the combination of several traps allows one to isobarically clean the sample prior to the in-trap decay spectroscopy measurement. This technique has been developed to measure ECBRs of transition nuclei in ββ decays. Detailed knowledge of these electron capture branches is crucial for a better understanding of the underlying nuclear physics in ββ decays. These branches are typically of the order of 10 -5 and therefore difficult to measure. Conventional measurements suffer from isobaric contamination and a dominating β background at theX-ray detector. Additionally, X-rays are attenuated by the material where the radioactive sample is implanted. To overcome these limitations, the technique of in-trap decay spectroscopy has been developed. In this work, the EBIT was connected to the TITAN beam line and has been commissioned. Using the developed beam diagnostics, ions were injected into the Penning trap and systematic studies on injection and storage optimization were performed. Furthermore, Ge detectors, for the detection of X-rays, were

  1. Decay tank

    International Nuclear Information System (INIS)

    Matsumura, Seiichi; Tagishi, Akinori; Sakata, Yuji; Kontani, Koji; Sudo, Yukio; Kaminaga, Masanori; Kameyama, Iwao; Ando, Koei; Ishiki, Masahiko.

    1990-01-01

    The present invention concerns an decay tank for decaying a radioactivity concentration of a fluid containing radioactive material. The inside of an decay tank body is partitioned by partitioning plates to form a flow channel. A porous plate is attached at the portion above the end of the partitioning plate, that is, a portion where the flow is just turned. A part of the porous plate has a slit-like opening on the side close to the partitioning plate, that is, the inner side of the flow at the turning portion thereof. Accordingly, the primary coolants passed through the pool type nuclear reactor and flown into the decay tank are flow caused to uniformly over the entire part of the tank without causing swirling. Since a distribution in a staying time is thus decreased, the effect of decaying 16 N as radioactive nuclides in the primary coolants is increased even in a limited volume of the tank. (I.N.)

  2. Relativistic ion collisions as the source of hypernuclei

    Energy Technology Data Exchange (ETDEWEB)

    Botvina, A.S. [J.W. Goethe University, Frankfurt Institute for Advanced Studies, Frankfurt am Main (Germany); Russian Academy of Sciences, Institute for Nuclear Research, Moscow (Russian Federation); Bleicher, M.; Steinheimer, J. [J.W. Goethe University, Frankfurt Institute for Advanced Studies, Frankfurt am Main (Germany); Pochodzalla, J. [J. Gutenberg-Universitaet, Helmholtz-Institut Mainz, Mainz (Germany); J. Gutenberg-Universitaet Mainz, Institut fuer Kernphysik and PRISMA Cluster of Excellence, Mainz (Germany)

    2016-08-15

    We shortly review the theory of hypernuclei production in relativistic ion collisions, that is adequate to future experiments at BM rate at N, NICA, and FAIR. Within a hybrid approach we use transport, coalescence and statistical models to describe the whole process. We demonstrate that the origin of hypernuclei can be explained by typical baryon interactions, that is similar to the production of conventional nuclei. In particular, heavy hypernuclei are coming mostly from projectile and target residues, whereas light hypernuclei can be produced at all rapidities. The yields of hypernuclei increase considerably above the energy threshold for Λ hyperon production, and there is a tendency to saturation of yields of hypernuclei with increasing the beam energy up to few TeV. There are unique opportunities in relativistic ion collisions which are difficult to realize in traditional hypernuclear experiments: The produced hypernuclei have a broad distribution in masses and isospin. They can even reach beyond the neutron and proton drip-lines and that opens a chance to investigate properties of exotic hypernuclei. One finds also the abundant production of multi-strange nuclei, of bound and unbound hypernuclear states with new decay modes. In addition, we can directly get an information on the hypermatter both at high and low temperatures. (orig.)

  3. Hadronic decay of late-decaying particles and big-bang nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Kawasaki, Masahiro [Research Center for the Early Universe, Graduate School of Science, University of Tokyo, Tokyo 113-0033 (Japan)]. E-mail: masahiro_kawasaki@mac.com; Kohri, Kazunori [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Moroi, Takeo [Department of Physics, Tohoku University, Sendai 980-8578 (Japan)

    2005-10-06

    We study the big-bang nucleosynthesis (BBN) scenario with late-decaying exotic particles with lifetime longer than {approx}1 s. With a late-decaying particle in the early universe, predictions of the standard BBN scenario can be significantly altered. Therefore, we derive constraints on its primordial abundance. We pay particular attention to hadronic decay modes of such particles. We see that the non-thermal production process of D, {sup 3}He and {sup 6}Li provides a stringent upper bound on the primordial abundance of late-decaying particles with hadronic branching ratio.

  4. Rare decays and CP asymmetries in charged B decays

    International Nuclear Information System (INIS)

    Deshpande, N.G.

    1991-01-01

    The theory of loop induced rare decays and the rate asymmetry due to CP violation in charged B Decays in reviewed. After considering b → sγ and b → se + e - decays, the asymmetries for pure penguin process are estimated first. A larger asymmetry can result in those modes where a tree diagram and a penguin diagram interfere, however these estimates are necessarily model dependent. Estimates of Cabbibo suppressed penguins are also considered

  5. a Search for Nucleon Decay with Multiple Muon Decays

    Science.gov (United States)

    Phillips, Thomas James

    A search was made for nucleon decays which result in multiple delayed muon decays using the HPW (Harvard -Purdue-Wisconsin) water Cerenkov detector. The HPW detector consists of 680 metric tons of purified water instrumented with 704 five-inch photomultiplier tubes. The phototubes are situated on a volume array with a lattice spacing of approximately one meter, and the inside walls of the detector are lined with mirrors. This combination of mirrors and a volume array of phototubes gives the HPW detector a low trigger energy threshold and a high muon decay detection efficiency. The detector is surrounded by wire chambers to provide an active shield, and is located at a depth of 1500 meters-of-water-equivalent in the Silver King Mine in Park City, Utah. The entire HPW data set, consisting of 17.2 million events collec- ted during 282 live days between May 1983 and October 1984, was analyzed. No contained events with multiple muon decays were found in a 180 ton fiducial volume. This is consistent with the background rate from neutrino interactions, which is expected to be 0.7 (+OR-) 0.2 events. The calculated lower lifetime limit for the decay mode p (--->) (mu)('+)(mu)('+)(mu)('-) is: (tau)/B.R. = 1 x 10('31) years (90% C.L.). Limits are calculated for ten other proton decay modes and five bound neutron decay modes, most of which are around 4 x 10('30) years (90% C.L.). No previous studies have reported results from direct searches for eight of these modes.

  6. Radioactive Decay

    Science.gov (United States)

    Radioactive decay is the emission of energy in the form of ionizing radiation. Example decay chains illustrate how radioactive atoms can go through many transformations as they become stable and no longer radioactive.

  7. The HypHI Phase 0 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Saito, T.R. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Inst. fuer Kernphysik, Johannes Gutenberg Univ. Mainz, J.J.Becherweg 45, 55099 Mainz (Germany)], E-mail: t.saito@gsi.de; Bianchin, S. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Borodina, O. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Inst. fuer Kernphysik, Johannes Gutenberg Univ. Mainz, J.J. Becherweg 45, 55099 Mainz (Germany); Bozkurt, V.; Goekuezuem, B. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Dept. of Physics, Nigde Univ., 51100 Nigde (Turkey); Kavatsyuk, M. [KVI, Zernikelaan 25, NL-9747 AA Groningen (Netherlands); Kim, E. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Dept. of Physics and Astronomy, Seoul National Univ., Gwanakro Sillim-dong, Gwanak-gu, Seoul 151-747 (Korea, Republic of); Minami, S. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Nakajima, D. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Dept. of Physics, Graduate School of Science, Univ. of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Ozel-Tashenov, B. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Rappold, C. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Univ. Louis Pasteur Strasbourg, 4 rue Blaise Pascal, 67070 Strasbourg Cedex (France); Achenbach, P. [Inst. fuer Kernphysik, Johannes Gutenberg Univ. Mainz, J.J.Becherweg 45, 55099 Mainz (Germany); Ajimura, S. [Research Center for Nuclear Physics (RCNP), 10-1 Mihogaoka, Ibaraki, Osaka, 567-0047 (Japan); Aumann, T.; Caesar, C. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany)] (and others)

    2010-04-01

    The HypHI Phase 0 experiment to demonstrate the feasibility of precise hypernuclear spectroscopy with induced reactions of heavy ion beams was performed at GSI in August and October in 2009, with a projectile of {sup 6}Li at 2 A GeV impinged on carbon graphite target with a thickness of 8 g/cm{sup 2}. The experiment mainly aims to reconstruct events of {sup 3}{sub {lambda}}H, {sup 4}{sub {lambda}}H and {sup 5}{sub {lambda}}He by observing the {pi}{sup -} decay channel. Details of the HypHI Phase 0 experiment performed in August in 2009 will be discussed.

  8. Selected problems in nuclear/high energy physics: Experimental hypernuclear physics, muon rare decay, and development of new detector system applicable to nuclear/high energy physics experiments. Final close-out report, June 1, 1994--May 31, 1997

    International Nuclear Information System (INIS)

    Tang, L.; Continuous Electron Beam Accelerator Facility, Newport News, VA

    1998-08-01

    spectrometer systems for strangeness S = -1 or -2 hypernuclear programs at either hadronic facilities such as BNL and KEK (or JHF-50 the new Japanese 50 GeV proton accelerator) or electron facility (mainly CEBAF). The fission chamber has been built and tested by source in lab and it is now under beam test. The optical design of the S2S spectrometer was presented in AGS-2000 Workshop (1996) and recently in JHF98 International Conference

  9. The Monte-Carlo code DECAY to simulate the decay of baryon and meson resonances

    International Nuclear Information System (INIS)

    Haenssgen, K.; Ritter, S.

    1983-01-01

    The code DECAY simulates the decay of unpolarized baryon and meson resonances in the laboratory frame. DECAY treats some resonances among these all baryon resonances of the spin 3/2 + decuplet and all meson resonances of the spin 1 - nonet. A given resonance decays via two or three particle decay steps until all decay products are stable particles. Program summary and code description are given. (author)

  10. Beta-decay and decay heat. Summary report of consultants' meeting

    International Nuclear Information System (INIS)

    Nicols, A.L.

    2006-01-01

    Experts on decay data and decay heat calculations participated in a Consultants' Meeting organized at IAEA Headquarters on 12-14 December 2005. Debate focused on the validation of decay heat calculations as a function of cooling time for fuel irradiated in power reactors through comparisons with experimental benchmark data. Both the current understanding and quantification of mean beta and gamma decay energies were reviewed with respect to measurements and the Gross Theory of Beta Decay. Particular emphasis was placed on the known development of total absorption gamma-ray spectroscopy (TAGS), and detailed discussions took place to formulate the measurement requirements for mean beta and gamma data of individual radionuclides. This meeting was organized in cooperation with the OECD/NEA Working Party for Evaluation and Cooperation (WPEC). Proposals and recommendations were made to resolve particular difficulties, and an initial list of fission products was produced for TAGS studies. The discussions, conclusions and recommendations of the meeting are briefly described in this report. (author)

  11. CP violation in K decays and rare decays

    International Nuclear Information System (INIS)

    Buchalla, G.

    1996-12-01

    The present status of CP violation in decays of neutral kaons is reviewed. In addition selected rare decays of both K and B mesons are discussed. The emphasis is in particular on observables that can be reliably calculated and thus offer the possibility of clean tests of standard model flavor physics. 105 refs

  12. Charm Decays at BABAR

    International Nuclear Information System (INIS)

    Charles, M.

    2004-01-01

    The results of several studies of charmed mesons and baryons at BABAR are presented. First, searches for the rare decays D 0 → l + l - are presented and new upper limits on these processes are established. Second, a measurement of the branching fraction of the isospin-violating hadronic decay D* s (2112) + → D s + π 0 relative to the radiative decay D* s (2112) + → D s + γ is made. Third, the decays of D* sJ (2317) + and D sJ (2460) + mesons are studied and ratios of branching fractions are measured. Fourth, Cabibbo-suppressed decays of the Λ c + are examined and their branching fractions measured relative to Cabibbo-allowed modes. Fifth, the Χ c 0 is studied through its decays to Χ - π + and (Omega) - K + ; in addition to measuring the ratio of branching fractions for Χ c 0 produced from the c(bar c) continuum, the uncorrected momentum spectrum is measured, providing clear confirmation of Χ c 0 production in B decays

  13. Rare B decays, rare τ decays, and grand unification

    International Nuclear Information System (INIS)

    Sher, M.; Yuan, Y.

    1991-01-01

    In multi-Higgs-boson extensions of the standard model, tree-level flavor-changing neutral currents exist naturally, unless suppressed by some symmetry. For a given rate, the exchanged scalar or pseudoscalar mass is very sensitive to the flavor-changing coupling between the first two generations. Since the Yukawa couplings of the first two generations are unknown and certainly very small, bounds which rely on some assumed value of this flavor-changing coupling are quite dubious. One might expect the size (and reliability) of the Yukawa couplings involving the third generation to be greater. In this paper, we consider processes involving τ's and B's, and determine the bounds on the flavor-changing couplings which involve third-generation fields. The strongest bound in the quark sector comes from B-bar B mixing and in the lepton sector, surprisingly, from μ→eγ. It is then noted that the flavor-changing couplings in the quark sector are related to those in the lepton sector in many grand unified theories, and one can ask whether an analysis of rare τ decays or rare B decays will provide the strongest constraints. We show that rare B decays provide the strongest bounds, and that no useful information can be obtained from rare τ decays. It is also noted that the most promising decay modes are B→Kμτ and B s →μτ, and we urge experimenters to look for rare decay modes of the B in which a τ is in the final state

  14. Column: Factors Affecting Data Decay

    Directory of Open Access Journals (Sweden)

    Kevin Fairbanks

    2012-06-01

    Full Text Available In nuclear physics, the phrase decay rate is used to denote the rate that atoms and other particles spontaneously decompose. Uranium-235 famously decays into a variety of daughter isotopes including Thorium and Neptunium, which themselves decay to others. Decay rates are widely observed and wildly different depending on many factors, both internal and external. U-235 has a half-life of 703,800,000 years, for example, while free neutrons have a half-life of 611 seconds and neutrons in an atomic nucleus are stable.We posit that data in computer systems also experiences some kind of statistical decay process and thus also has a discernible decay rate. Like atomic decay, data decay fluctuates wildly. But unlike atomic decay, data decay rates are the result of so many different interplaying processes that we currently do not understand them well enough to come up with quantifiable numbers. Nevertheless, we believe that it is useful to discuss some of the factors that impact the data decay rate, for these factors frequently determine whether useful data about a subject can be recovered by forensic investigation.(see PDF for full column

  15. Visual cues for woodpeckers: light reflectance of decayed wood varies by decay fungus

    Science.gov (United States)

    O'Daniels, Sean T.; Kesler, Dylan C.; Mihail, Jeanne D.; Webb, Elisabeth B.; Werner, Scott J.

    2018-01-01

    The appearance of wood substrates is likely relevant to bird species with life histories that require regular interactions with wood for food and shelter. Woodpeckers detect decayed wood for cavity placement or foraging, and some species may be capable of detecting trees decayed by specific fungi; however, a mechanism allowing for such specificity remains unidentified. We hypothesized that decay fungi associated with woodpecker cavity sites alter the substrate reflectance in a species-specific manner that is visually discriminable by woodpeckers. We grew 10 species of wood decay fungi from pure cultures on sterile wood substrates of 3 tree species. We then measured the relative reflectance spectra of decayed and control wood wafers and compared them using the receptor noise-limited (RNL) color discrimination model. The RNL model has been used in studies of feather coloration, egg shells, flowers, and fruit to model how the colors of objects appear to birds. Our analyses indicated 6 of 10 decayed substrate/control comparisons were above the threshold of discrimination (i.e., indicating differences discriminable by avian viewers), and 12 of 13 decayed substrate comparisons were also above threshold for a hypothetical woodpecker. We conclude that woodpeckers should be capable of visually detecting decayed wood on trees where bark is absent, and they should also be able to detect visually species-specific differences in wood substrates decayed by fungi used in this study. Our results provide evidence for a visual mechanism by which woodpeckers could identify and select substrates decayed by specific fungi, which has implications for understanding ecologically important woodpecker–fungus interactions.

  16. Rare Decays at LHCb

    CERN Document Server

    Belyaev, Ivan

    2006-01-01

    Rare loop-induced decays are sensitive to New Physics in many Standard Model extensions. In this paper we discuss the reconstruction of the radiative penguin decays $B^0_d \\to K^{*0} \\gamma, B^0_s \\to \\phi \\gamma , B^0_d \\to \\omega \\gamma, \\Lambda_b \\to \\Lambda \\gamma$, the electroweak penguin decays $B^0_d \\to K^{*0} \\mu^+ \\mu^-, B^+_u \\to K^+ \\mu^+ \\mu^-$, the gluonic penguin decays $B^0_d \\to \\phi K^0_S, B^0_s \\to \\phi \\phi$, and the decay $B^0_s \\to \\mu^+\\mu^-$ at LHCb. The selection criteria, evaluated efficiencies, expected annual yields and $B/S$ estimates are presented.

  17. Evidence for the electromagnetic decay instability driven by two plasmon decay

    International Nuclear Information System (INIS)

    Baker, K.L.; Afeyan, B.B.; Estabrook, K.G.; Drake, R.P.

    1997-01-01

    This paper examines the electromagnetic decay instability (EDI) and its role in laser-produced plasmas. The electromagnetic decay instability provides another channel through which parametric instabilities involving Langmuir waves can saturate. In the case where EDI is pumped by the Langmuir waves associated with two plasmon decay, EDI is shown to present an explanation for ω o /2 emission from laser-produced plasmas which is consistent with experimental observations

  18. Tau decays

    International Nuclear Information System (INIS)

    Golutvin, A.

    1994-09-01

    The most recent experimental results of τ physics are reviewed. The covered topics include precision measurements of semihadronic τ decay and their impact on tau branching ratio budget, the current status of the tau consistency test, a determination of Michel parameters and τ neutrino helicity, and upper limits on lepton-number violating τ decays. (orig.)

  19. Experimental medium energy physics. Annual progress report, June 1983-May 1984

    International Nuclear Information System (INIS)

    1984-01-01

    During the past year the principal activities of the C-MU Medium Energy Physics Group have included running of previously approved experiments, the development of hardware and software for new experiments, continued analysis of previously accumulated data, and the development of model calculations to be compared with these data. Major data runs have taken place on a hypernuclear experiment (AGS 781) at the AGS, and on an antiproton run at CERN/LEAR (PS-185). In addition, planning is continuing for further hypernuclear lifetime measurements in 4 5 He, and for a possible search for the H-particle. For these experiments extensive hardware and software development has taken place, requiring much of the group's effort. In our ongoing studies of the pion annihilation mechanism, the emphasis has shifted from two-body processes to those involving three-body final states. A large effort is being devoted to the analysis of our (π,xy) data accumulated at LAMPF on targets of 6 7 Li, 14 N, 16 O and CD 2 . During the year considerable effort was devoted to Monte Carlo simulations of the rare weak decay K + → π + nu anti nu; this experiment has been approved as AGS 787. In addition, work has continued on the development of model calculations of the (π,pp) and anti pp → anti ΛΛ reactions

  20. The (π+,K+) reaction: Past, present, and future

    International Nuclear Information System (INIS)

    Chrien, R.E.

    1990-01-01

    The (π + , K + ) reaction applied to hypernuclear research is discussed. A brief history of its origins and its relation to strangeness changing reactions (K - , π - ) is given, and the current status of the field is described. Some ideas for future hypernuclear research are discussed and some specific examples treated. 21 refs., 7 figs., 2 tabs

  1. Decays of supernova neutrinos

    International Nuclear Information System (INIS)

    Lindner, Manfred; Ohlsson, Tommy; Winter, Walter

    2002-01-01

    Supernova neutrinos could be well-suited for probing neutrino decay, since decay may be observed even for very small decay rates or coupling constants. We will introduce an effective operator framework for the combined description of neutrino decay and neutrino oscillations for supernova neutrinos, which can especially take into account two properties: one is the radially symmetric neutrino flux, allowing a decay product to be re-directed towards the observer even if the parent neutrino had a different original direction of propagation. The other is decoherence because of the long baselines for coherently produced neutrinos. We will demonstrate how to use this effective theory to calculate the time-dependent fluxes at the detector. In addition, we will show the implications of a Majoron-like decay model. As a result, we will demonstrate that for certain parameter values one may observe some effects which could also mimic signals similar to the ones expected from supernova models, making it in general harder to separate neutrino and supernova properties

  2. Rare psi decays

    International Nuclear Information System (INIS)

    Partridge, R.

    1986-01-01

    Slightly more than ten years have passed since the psi was discovered, yet the study of psi decays continues to be an active and fruitful area of research. One reason for such longevity is that each successive experiment has increased their sensitivity over previous experiments either by improving detection efficiency or by increasing statistics. This has allowed the observation and, in some cases, detailed studies of rare psi decays. Branching ratios of ≅10-/sup 4/ are now routinely studied, while certain decay channels are beginning to show interesting effects at the 10-/sup 5/ level. Future experiments at the Beijing Electron Positron Collider (BEPC) have the potential for increasing sensitivities by one or two orders of magnitude, thus enabling many interesting studies impossible with current data samples. The author first examines the extent to which psi decays can be used to study electroweak phenomena. The remainder of this work is devoted to the more traditional task of using the psi to study quarks, gluons, and the properties of the strong interaction. Of particular interest is the study of radioactive psi decays, where a number of new particles have been discovered. Recent results regarding two of these particles, the θ(1700) and iota(1450), are discussed, as well as a study of the quark content of the eta and eta' using decays of the psi to vector-pseudoscalar final states

  3. α-decay chains and cluster-decays of superheavy 269-27110 nuclei

    International Nuclear Information System (INIS)

    Sushil Kumar; Rajesh Kumar; Balasubramaniam, M.; Gupta, Raj K.

    2001-01-01

    Due to the availability of radioactive nuclear beams (RNB) and the advancement in accelerator technology, it is now possible to synthesize very heavy elements (Z> 100), called superheavy elements. It is a well established fact that these superheavy elements, due to their shorter lifetime, decay via successive alpha emissions and at a later stage undergo spontaneous fission. Several such decay chains are now observed. An attempt is made to fit all such known decay chains and the results of the three observed α-decay chains of Z=110 ( 269-271 10) nuclei are presented. The model used is the preformed cluster model (PCM). Also, an attempt is made for the first time to find the possibility of any branching to heavy-cluster emissions in these chains

  4. SYMPOSIUM: Rare decays

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1989-04-15

    Late last year, a symposium entitled 'Rare Decays' attracted 115 participants to a hotel in Vancouver, Canada. These participants were particle physicists interested in checking conventional selection rules to look for clues of possible new behaviour outside today's accepted 'Standard Model'. For physicists, 'rare decays' include processes that have so far not been seen, explicitly forbidden by the rules of the Standard Model, or processes highly suppressed because the decay is dominated by an easier route, or includes processes resulting from multiple transitions.

  5. CP violation in B decay

    OpenAIRE

    Yamamoto, Hitoshi

    2001-01-01

    We review the physics of CP violation in B decays. After introducing the CKM matrix and how it causes CP violation, we cover three types of CP violation that can occur in B decays: CP violation in mixing, CP violation by mixing-decay interference, and CP violation in decay.

  6. Charmless B-decays at LHCb

    CERN Document Server

    Eklund, Lars

    2016-01-01

    These proceedings summarise three recent papers from the LHCb Collaboration in the area of charmless b-decays. The branching fraction for the decay $\\text{B}_{s}^{0}\\rightarrow \\phi \\phi$ is measured and a search for the highly suppressed decay $\\text{B}^{0}\\rightarrow \\phi \\phi$ is performed. The decay $\\text{B}_{s}^{0}\\rightarrow {\\eta}'{\\eta}'$ is observed for the first time and the CP asymmetries in the decays $\\text{B}^{+}\\rightarrow {\\eta}'\\text{K}^{+}$ and $\\text{B}^{+}\\rightarrow \\phi \\text{K}^{+}$ are measured. Finally, the decay $\\text{B}^{0}\\rightarrow \\rho^{0}\\rho^{0}$ is observed for the first time and its longitudinal polarisation is measured.

  7. Aspects of B decays

    International Nuclear Information System (INIS)

    Faller, Sven

    2011-01-01

    B-meson decays are a good probe for testing the flavour sector of the standard model of particle physics. The standard model describes at present all experimental data satisfactorily, although some ''tensions'' exist, i.e. two to three sigma deviations from the predictions, in particular in B decays. The arguments against the standard model are thus purely theoretical. These tensions between experimental data and theoretical predictions provide an extension of the standard model by new physics contributions. Within the flavour sector main theoretical uncertainties are related to the hadronic matrix elements. For exclusive semileptonic anti B → D (*) l anti ν decays QCD sum rule techniques, which are suitable for studying hadronic matrix elements, however, with substantial, but estimable hadronic uncertainties, are used. The exploration of new physics effects in B-meson decays is done in an twofold way. In exclusive semileptonic anti B → D (*) l anti ν decays the effect of additional right-handed vector as well as left- and right-handed scalar and tensor hadronic current structures in the decay rates and the form factors are studied at the non-recoil point. As a second approach one studied the non-leptonic B 0 s →J/ψφ and B 0 →J/ψK S,L decays discussing CP violating effects in the time-dependent decay amplitudes by considering new physics phase in the B 0 - anti B 0 mixing phase. (orig.)

  8. Rare B decays at LHCb

    CERN Document Server

    Puig Navarro, Albert

    2017-01-01

    Rare decays are flavour changing neutral current processes that allow sensitive searches for phenomena beyond the Standard Model (SM). In the SM, rare decays are loop-suppressed and new particles in SM extensions can give significant contributions. The very rare decay $B^0_s\\to\\mu^+\\mu^-$ in addition helicity suppressed and constitutes a powerful probe for new (pseudo) scalar particles. Of particular interest are furthermore tests of lepton universality in rare $b\\to s\\ell^+\\ell^-$ decays. The LHCb experiment is designed for the study of b-hadron decays and ideally suited for the analysis of rare decays due to its high trigger efficiency, as well as excellent tracking and particle identification performance. Recent results from the LHCb experiment in the area of rare decays are presented, including tests of lepton universality and searches for lepton flavour violation.

  9. MODEL RADIOACTIVE RADON DECAY

    Directory of Open Access Journals (Sweden)

    R.I. Parovik

    2012-06-01

    Full Text Available In a model of radioactive decay of radon in the sample (222Rn. The model assumes that the probability of the decay of radon and its half-life depends on the fractal properties of the geological environment. The dependencies of the decay parameters of the fractal dimension of the medium.

  10. Rare and forbidden decays

    CERN Document Server

    Trampetic, Josip

    2002-01-01

    In these lectures I first cover radiative and semileptonic B decays, including the QCD corrections for the quark subprocesses. The exclusive modes and the evaluation of the hadronic matrix elements, i.e. the relevant hadronic form factors, are the second step. Small effects due to the long-distance, spectator contributions, etc. are discussed next. The second section we started with non-leptonic decays, typically $B \\to \\pi\\pi, K\\pi, \\rho\\pi,...$ We describe in more detail our prediction for decays dominated by the $b\\to s \\eta_c$ transition. Reports on the most recent experimental results are given at the end of each subsection. In the second part of the lectures I discuss decays forbidden by the Lorentz and gauge invariance, and due to the violation of the angular moment conservation, generally called the Standard Model-forbiden decays. However, the non-commutative QED and/or non-commutative Standard Model (NCSM), developed in a series of works in the last few years allow some of those decay modes. These ar...

  11. Radioactive decay and labeled compounds

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    This chapter on radioactive decay and labeled compounds has numerous intext equations and worked, sample problems. Topics covered include the following: terms and mathematics of radioactive decay; examples of calculations; graphs of decay equations; radioactivity or activity; activity measurements; activity decay; half-life determinations; labeled compounds. A 20 problem set is also included. 1 ref., 4 figs., 1 tab

  12. SYMPOSIUM: Rare decays

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    Late last year, a symposium entitled 'Rare Decays' attracted 115 participants to a hotel in Vancouver, Canada. These participants were particle physicists interested in checking conventional selection rules to look for clues of possible new behaviour outside today's accepted 'Standard Model'. For physicists, 'rare decays' include processes that have so far not been seen, explicitly forbidden by the rules of the Standard Model, or processes highly suppressed because the decay is dominated by an easier route, or includes processes resulting from multiple transitions

  13. B decays to open charm

    CERN Document Server

    AUTHOR|(CDS)2073670

    2016-01-01

    Studies of $B$ meson decays to states involving open charm mesons in data recorded by the LHCb experiment have resulted in first observations of several new decay modes, including $B_s^{0} \\rightarrow D_s^{*\\mp} K^{\\pm}$, $B_s^{0} \\rightarrow \\overline{D}^{0} K_S^{0}$ and $B^{+} \\rightarrow D^{+} K^{+} \\pi^{-}$ decays. An upper limit has been placed on the branching fraction of $B_s^{0} \\rightarrow \\overline{D}^{0} f_0(980)$ decays. Measurements of other branching fractions, such as those of $B_s^{0} \\rightarrow D_s^{(*)+} D_s^{(*)-}$ decays, are the most precise to date. Additionally, amplitude analyses of $B^{0} \\rightarrow \\overline{D}^{0} \\pi^{+} \\pi^{-}$ and $B^{0} \\rightarrow \\overline{D}^{0} K^{+} \\pi^{-}$ decays have been performed, alongside the first $CP$ violation analysis using the Dalitz plot of $B^{0} \\rightarrow D K^{+} \\pi^{-}$ decays.

  14. Aspects of B decays

    Energy Technology Data Exchange (ETDEWEB)

    Faller, Sven

    2011-03-04

    B-meson decays are a good probe for testing the flavour sector of the standard model of particle physics. The standard model describes at present all experimental data satisfactorily, although some ''tensions'' exist, i.e. two to three sigma deviations from the predictions, in particular in B decays. The arguments against the standard model are thus purely theoretical. These tensions between experimental data and theoretical predictions provide an extension of the standard model by new physics contributions. Within the flavour sector main theoretical uncertainties are related to the hadronic matrix elements. For exclusive semileptonic anti B {yields} D{sup (*)}l anti {nu} decays QCD sum rule techniques, which are suitable for studying hadronic matrix elements, however, with substantial, but estimable hadronic uncertainties, are used. The exploration of new physics effects in B-meson decays is done in an twofold way. In exclusive semileptonic anti B {yields} D{sup (*)}l anti {nu} decays the effect of additional right-handed vector as well as left- and right-handed scalar and tensor hadronic current structures in the decay rates and the form factors are studied at the non-recoil point. As a second approach one studied the non-leptonic B{sup 0}{sub s}{yields}J/{psi}{phi} and B{sup 0}{yields}J/{psi}K{sub S,L} decays discussing CP violating effects in the time-dependent decay amplitudes by considering new physics phase in the B{sup 0}- anti B{sup 0} mixing phase. (orig.)

  15. Strength loss in decayed wood

    Science.gov (United States)

    Rebecca E. Ibach; Patricia K. Lebow

    2014-01-01

    Wood is a durable engineering material when used in an appropriate manner, but it is susceptible to biological decay when a log, sawn product, or final product is not stored, handled, or designed properly. Even before the biological decay of wood becomes visually apparent, the decay can cause the wood to become structurally unsound. The progression of decay to that...

  16. Interatomic Coulombic decay following the Auger decay: Experimental evidence in rare-gas dimers

    International Nuclear Information System (INIS)

    Ueda, K.; Fukuzawa, H.; Liu, X.-J.; Sakai, K.; Pruemper, G.; Morishita, Y.; Saito, N.; Suzuki, I.H.; Nagaya, K.; Iwayama, H.; Yao, M.; Kreidi, K.; Schoeffler, M.; Jahnke, T.; Schoessler, S.; Doerner, R.; Weber, Th.; Harries, J.; Tamenori, Y.

    2008-01-01

    Interatomic Coulombic decay (ICD) in Ar 2 , ArKr and Kr 2 following Ar 2p or Kr 3d Auger decay has been investigated by means of momentum-resolved electron-ion-ion coincidence spectroscopy. This sequential decay leads to Coulombic dissociation into dication and monocation. Simultaneously determining the kinetic energy of the ICD electron and the kinetic energy release between the two atomic ions, we have been able to unambiguously identify the ICD channels. We find that, in general, spin-conserved ICD, in which the singlet (triplet) dicationic state produced via the atomic Auger decay preferentially decays to the singlet (triplet) state, transferring the energy to the other atom, is faster than spin-flip ICD, in which the Auger final singlet (triplet) dicationic state decays to the triplet (singlet) state. However, spin-flip ICD may take place when spin-conserved ICD becomes energetically forbidden. Dipole-forbidden ICDs from Kr 2+ (4s -21 S)-B (B = Ar or Kr) to Kr 2+ (4p -21 D, 3 P)-B + are also observed

  17. To decay or not to decay - or both ! quantum mechanics of spontaneous emission

    DEFF Research Database (Denmark)

    Kristensen, Philip Trøst; Lodahl, Peter; Mørk, Jesper

    2008-01-01

    We discuss calculations of spontaneous emission from quantum dots in photonic crystals and show how the decay depends on the intrinsic properties of the emitter as well as the position. A number of fundamentally different types of spontaneous decay dynamics are shown to be possible, including...... counter intuitive situations in which the quantum dot decays only partially....

  18. Axigluon decays of toponium

    International Nuclear Information System (INIS)

    Faustov, R.N.; Vasilevskaya, I.G.

    1990-01-01

    Chiral-colour model predicts the existence of axigluons which is an octet of massive axial-vector gauge bosons. In this respect toponium decays into axigluons and gluons are of interest. The following toponium decays are considered: θ → Ag, θ → AAg, θ → ggg → AAg. The width of toponium S-state decays is calculated under various possible values of axigluon mass

  19. RADIATIVE PENGUIN DECAYS FROM BABAR

    Energy Technology Data Exchange (ETDEWEB)

    Eigen, Gerald

    2003-08-28

    Electroweak penguin decays provide a promising hunting ground for Physics beyond the Standard Model (SM). The decay B {yields} X{sub s}{gamma}, which proceeds through an electromagnetic penguin loop, already provides stringent constraints on the supersymmetric (SUSY) parameter space. The present data samples of {approx}1 x 10{sup 8} B{bar B} events allow to explore radiative penguin decays with branching fractions of the order of 10{sup -6} or less. In this brief report they discuss a study of B {yields} K*{ell}{sup +}{ell}{sup -} decay modes and a search for B {yields} {rho}({omega}){gamma} decays.

  20. Charmless Hadronic Beauty Decays at LHCb

    Directory of Open Access Journals (Sweden)

    Williams Timothy

    2017-01-01

    Full Text Available A summary of six LHCb results on the topic of charmless hadronic b-hadron decays is presented. These are comprised of: a search for the decay Bs0→Ks0K+K− and updated branching fraction measurements of B(s0→Ks0h+h′− decays (h=K,π [1]; the first observation of the decays B0→pp¯π+π−,  Bs0→pp¯K+K−,Bs0→pp¯K+π− and strong evidence for the decay B0→pp¯K+K− [2]; the first observation of the decay Bs0→pΛ¯K− [3]; a search for the decay Bs0→φη′ [4]; the first observation of the decay Ξb−→pK−K− [5] and evidence for CP-violation in Λb0→pπ−π+π− decays [6].

  1. Decay of 143La

    International Nuclear Information System (INIS)

    Blachot, J.; Dousson, S.; Monnand, E.; Schussler, F.

    1976-01-01

    The decay of 143 La has been investigated. Sources have been obtained from 2 isotope separators (ISERE, OSIRIS). 12 gamma rays, with the most intense at 620keV representing only 1.4% of decay, have been attributed to the 143 La decay. A level scheme has been found and compared with the one deduced from (d,p) and (n,γ) reactions on 142 Ce [fr

  2. JNDC FP decay data file

    International Nuclear Information System (INIS)

    Yamamoto, Tohru; Akiyama, Masatsugu

    1981-02-01

    The decay data file for fission product nuclides (FP DECAY DATA FILE) has been prepared for summation calculation of the decay heat of fission products. The average energies released in β- and γ-transitions have been calculated with computer code PROFP. The calculated results and necessary information have been arranged in tabular form together with the estimated results for 470 nuclides of which decay data are not available experimentally. (author)

  3. Exclusive semileptonic B-meson decays

    International Nuclear Information System (INIS)

    Hagiwara, K.; Martin, A.D.; Wade, M.F.

    1989-01-01

    We study the semileptonic processes anti B → D * lanti ν and anti B → Dlanti ν and show that the invariant hadronic form factors describing the decays can be measured directly by observing the angular correlations of the decay products. We emphasize that this allows an almost model-independent determination of the V cb quark mixing-matrix element. We examine the theoretical models for the form factors in terms of the spectator quark approach. We present a general formalism for semileptonic decays which includes lepton mass effects, since the decay into τ-leptons may be important as background events in the search for rare decay modes involving missing particles. (orig.)

  4. Shannon entropy and particle decays

    Science.gov (United States)

    Carrasco Millán, Pedro; García-Ferrero, M. Ángeles; Llanes-Estrada, Felipe J.; Porras Riojano, Ana; Sánchez García, Esteban M.

    2018-05-01

    We deploy Shannon's information entropy to the distribution of branching fractions in a particle decay. This serves to quantify how important a given new reported decay channel is, from the point of view of the information that it adds to the already known ones. Because the entropy is additive, one can subdivide the set of channels and discuss, for example, how much information the discovery of a new decay branching would add; or subdivide the decay distribution down to the level of individual quantum states (which can be quickly counted by the phase space). We illustrate the concept with some examples of experimentally known particle decay distributions.

  5. Ultra-Rare B Decays

    International Nuclear Information System (INIS)

    Grinstein, Benjamin

    2004-01-01

    A good place to look for deviations from the Standard Model is in decay modes of B mesons, like purely leptonic decays B → lv, for which a very long Standard Model lifetime is due to an accidental suppression of the decay amplitude. For other rare decay modes involving no hadrons in the final state (e.g., B → γl+l-, B → γlvl and B → vv-barγ) new results on QCD factorization in exclusive processes show that all the decay rates are given in terms of a single universal form factor. Hence, trustworthy relations between different processes can be used to test the Standard Model of electroweak interactions. Sometimes, surprisingly, a large energy expansion may allow computation when a hadron is in the final state. An example is B → πl+l- which can be used to settle the ambiguity in α from a measurement of sin2α from CP asymmetries

  6. Visible neutrino decay at DUNE

    Energy Technology Data Exchange (ETDEWEB)

    Coloma, Pilar [Fermilab; Peres, Orlando G. [ICTP, Trieste

    2017-05-09

    If the heaviest neutrino mass eigenstate is unstable, its decay modes could include lighter neutrino eigenstates. In this case part of the decay products could be visible, as they would interact at neutrino detectors via mixing. At neutrino oscillation experiments, a characteristic signature of such \\emph{visible neutrino decay} would be an apparent excess of events at low energies. We focus on a simple phenomenological model in which the heaviest neutrino decays as $\

  7. Inflaton decay in supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Endo, M.; Takahashi, F. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Yanagida, T.T. [Tokyo Univ. (Japan). Dept. of Physics]|[Tokyo Univ. (Japan). Research Center for the Early Universe

    2007-06-15

    We discuss inflaton decay in supergravity, taking account of the gravitational effects. It is shown that, if the inflaton has a nonzero vacuum expectation value, it generically couples to any matter fields that appear in the superpotential at the tree level, and to any gauge sectors through anomalies in the supergravity. Through these processes, the inflaton generically decays into the supersymmetry breaking sector, producing many gravitinos. The inflaton also directly decays into a pair of the gravitinos. We derive constraints on both inflation models and supersymmetry breaking scenarios for avoiding overproduction of the gravitinos. Furthermore, the inflaton naturally decays into the visible sector via the top Yukawa coupling and SU(3){sub C} gauge interactions. (orig.)

  8. Inflaton decay in supergravity

    International Nuclear Information System (INIS)

    Endo, M.; Takahashi, F.; Yanagida, T.T.; Tokyo Univ.

    2007-06-01

    We discuss inflaton decay in supergravity, taking account of the gravitational effects. It is shown that, if the inflaton has a nonzero vacuum expectation value, it generically couples to any matter fields that appear in the superpotential at the tree level, and to any gauge sectors through anomalies in the supergravity. Through these processes, the inflaton generically decays into the supersymmetry breaking sector, producing many gravitinos. The inflaton also directly decays into a pair of the gravitinos. We derive constraints on both inflation models and supersymmetry breaking scenarios for avoiding overproduction of the gravitinos. Furthermore, the inflaton naturally decays into the visible sector via the top Yukawa coupling and SU(3) C gauge interactions. (orig.)

  9. The π+ Decay of Light Hypernuclei

    International Nuclear Information System (INIS)

    Gibson, B.F.

    1999-01-01

    The observed π + emission from the weak decay of the 4 Λ He hypernucleus has been an intriguing puzzle for more than 30 years, because the Lambda decays in free space only by emission of a π - or a π 0 . We re-examine this puzzling weak decay with our focus upon a decay mechanism involving the Σ + N r a rrow π + nN decay of a virtual Σ + , stemming from ΛN to ΣN conversion (mixing) within the hypernucleus. We emphasize the observed energy distribution of the observed π + s compared to that of π - s in standard mesonic decay as well as the isotropic angular distribution of the π + s. Competing suggestions to explain the positive pion weak decay have been offered. A possible search for π + decay from the other Λ hypernuclei is explored as means to test our hypothesis

  10. Search for new mechanism of CP violation through tau decay and semileptonic decay at hadrons

    International Nuclear Information System (INIS)

    Tsai, Yung Su.

    1996-11-01

    If CP is violated in any decay process involving leptons it will signify the existence of a new force (called the X boson) responsible for CP violation that may be the key to understanding matter-antimatter asymmetry in the universe. The author discusses the signatures of CP violation in (1) the decay of tau lepton, and (2) the semileptonic decay of π, K, D, B and t particles by measuring the polarization of the charged lepton in the decay. The author discusses how the coupling constants and their phases of the coupling of the X boson to 9 quark vertices and 3 lepton vertices can be obtained through 12 decay processes

  11. Decay constants and radiative decays of heavy mesons in light-front quark model

    International Nuclear Information System (INIS)

    Choi, Ho-Meoyng

    2007-01-01

    We investigate the magnetic dipole decays V→Pγ of various heavy-flavored mesons such as (D,D*,D s ,D s *,η c ,J/ψ) and (B,B*,B s ,B s *,η b ,Υ) using the light-front quark model constrained by the variational principle for the QCD-motivated effective Hamiltonian. The momentum dependent form factors F VP (q 2 ) for V→Pγ* decays are obtained in the q + =0 frame and then analytically continued to the timelike region by changing q perpendicular to iq perpendicular in the form factors. The coupling constant g VPγ for real photon case is then obtained in the limit as q 2 →0, i.e. g VPγ =F VP (q 2 =0). The weak decay constants of heavy pseudoscalar and vector mesons are also calculated. Our numerical results for the decay constants and radiative decay widths for the heavy-flavored mesons are overall in good agreement with the available experimental data as well as other theoretical model calculations

  12. Sigma beta decay

    International Nuclear Information System (INIS)

    Newman, D.E.

    1975-01-01

    Describes an experiment to measure beta decays of the sigma particle. Sigmas produced by stopping a K - beam in a liquid hydrogen target decayed in the following reactions: Kp → Σπ; Σ → Neν. The electron and pion were detected by wire spark chambers in a magnetic spectrometer and by plastic scintillators, and were differentiated by a threshold gas Cherenkov counter. The neutron was detected by liquid scintillation counters. The data (n = 3) shell electrons or the highly excited electrons decay first. Instead, it is suggested that when there are two to five electrons in highly excited states immediately after a heavy ion--atom collision the first transitions to occur will be among highly excited Rydberg states in a cascade down to the 4s, 4p, and 3d-subshells. If one of the long lived states becomes occupied by electrons promoted during the collision or by electrons falling from higher levels, it will not decay until after the valence shell decays. LMM rates calculated to test the methods used are compared to previous works. The mixing coefficients are given in terms of the states 4s4p, 45sp+-, and 5s5p. The applicability of Cooper, Fano, and Prats' discussion of the energies and transition rates of doubly excited states is considered

  13. Iconic decay in schizophrenia.

    Science.gov (United States)

    Hahn, Britta; Kappenman, Emily S; Robinson, Benjamin M; Fuller, Rebecca L; Luck, Steven J; Gold, James M

    2011-09-01

    Working memory impairment is considered a core deficit in schizophrenia, but the precise nature of this deficit has not been determined. Multiple lines of evidence implicate deficits at the encoding stage. During encoding, information is held in a precategorical sensory store termed iconic memory, a literal image of the stimulus with high capacity but rapid decay. Pathologically increased iconic decay could reduce the number of items that can be transferred into working memory before the information is lost and could thus contribute to the working memory deficit seen in the illness. The current study used a partial report procedure to test the hypothesis that patients with schizophrenia (n = 37) display faster iconic memory decay than matched healthy control participants (n = 28). Six letters, arranged in a circle, were presented for 50 ms. Following a variable delay of 0-1000 ms, a central arrow cue indicated the item to be reported. In both patients and control subjects, recall accuracy decreased with increasing cue delay, reflecting decay of the iconic representation of the stimulus array. Patients displayed impaired memory performance across all cue delays, consistent with an impairment in working memory, but the rate of iconic memory decay did not differ between patients and controls. This provides clear evidence against faster loss of iconic memory representations in schizophrenia, ruling out iconic decay as an underlying source of the working memory impairment in this population. Thus, iconic decay rate can be added to a growing list of unimpaired cognitive building blocks in schizophrenia.

  14. Particle decay in inflationary cosmology

    International Nuclear Information System (INIS)

    Boyanovsky, D.; Vega, H.J. de

    2004-01-01

    We investigate the relaxation and decay of a particle during inflation by implementing the dynamical renormalization group. This investigation allows us to give a meaningful definition for the decay rate in an expanding universe. As a prelude to a more general scenario, the method is applied here to study the decay of a particle in de Sitter inflation via a trilinear coupling to massless conformally coupled particles, both for wavelengths much larger and much smaller than the Hubble radius. For superhorizon modes we find that the decay is of the form η Γ 1 with η being conformal time and we give an explicit expression for Γ 1 to leading order in the coupling which has a noteworthy interpretation in terms of the Hawking temperature of de Sitter space-time. We show that if the mass M of the decaying field is << H then the decay rate during inflation is enhanced over the Minkowski space-time result by a factor 2H/πM. For wavelengths much smaller than the Hubble radius we find that the decay law is e with C(η) the scale factor and α determined by the strength of the trilinear coupling. In all cases we find a substantial enhancement in the decay law as compared to Minkowski space-time. These results suggest potential implications for the spectrum of scalar density fluctuations as well as non-Gaussianities

  15. β decay studies of n-rich Cs isotopes with the ISOLDE Decay Station

    Science.gov (United States)

    Lică, R.; Benzoni, G.; Morales, A. I.; Borge, M. J. G.; Fraile, L. M.; Mach, H.; Madurga, M.; Sotty, C.; Vedia, V.; De Witte, H.; Benito, J.; Berry, T.; Blasi, N.; Bracco, A.; Camera, F.; Ceruti, S.; Charviakova, V.; Cieplicka-Oryńczak, N.; Costache, C.; Crespi, F. C. L.; Creswell, J.; Fernández-Martínez, G.; Fynbo, H.; Greenlees, P.; Homm, I.; Huyse, M.; Jolie, J.; Karayonchev, V.; Köster, U.; Konki, J.; Kröll, T.; Kurcewicz, J.; Kurtukian-Nieto, T.; Lazarus, I.; Leoni, S.; Lund, M.; Marginean, N.; Marginean, R.; Mihai, C.; Mihai, R.; Negret, A.; Orduz, A.; Patyk, Z.; Pascu, S.; Pucknell, V.; Rahkila, P.; Regis, J. M.; Rotaru, F.; Saed-Sami, N.; Sánchez-Tembleque, V.; Stanoiu, M.; Tengblad, O.; Thuerauf, M.; Turturica, A.; Van Duppen, P.; Warr, N.

    2017-05-01

    Neutron-rich Ba isotopes are expected to exhibit octupolar correlations, reaching their maximum in isotopes around mass A = 146. The odd-A neutron-rich members of this isotopic chain show typical patterns related to non-axially symmetric shapes, which are however less marked compared to even-A ones, pointing to a major contribution from vibrations. In the present paper we present results from a recent study focused on 148-150Cs β-decay performed at the ISOLDE Decay Station equipped with fast-timing detectors. A detailed analysis of the measured decay half-lives and decay scheme of 149Ba is presented, giving a first insight in the structure of this neutron-rich nucleus.

  16. Three-body decays: structure, decay mechanism and fragment properties

    International Nuclear Information System (INIS)

    Alvarez-Rodriguez, R.; Jensen, A.S.; Fedorov, D.V.; Fynbo, H.O.U.; Kirsebom, O.S.; Garrido, E.

    2009-01-01

    We discuss the three-body decay mechanisms of many-body resonances. R-matrix sequential description is compared with full Faddeev computation. The role of the angular momentum and boson symmetries is also studied. As an illustration we show the computed ?-particle energy distribution after the decay of 12 C(1 + ) resonance at 12.7 MeV. This article is based on the presentation by R. Alvarez-Rodriguez at the Fifth Workshop on Critical Stability, Erice, Sicily. (author)

  17. Suppressed Charmed B Decay

    Energy Technology Data Exchange (ETDEWEB)

    Snoek, Hella Leonie [Vrije Univ., Amsterdam (Netherlands)

    2009-06-02

    This thesis describes the measurement of the branching fractions of the suppressed charmed B0 → D*- a0+ decays and the non-resonant B0 → D*- ηπ+ decays in approximately 230 million Υ(4S) → B$\\bar{B}$ events. The data have been collected with the BABAR detector at the PEP-II B factory at the Stanford Linear Accelerator Center in California. Theoretical predictions of the branching fraction of the B0 → D*- a{sub 0}+ decays show large QCD model dependent uncertainties. Non-factorizing terms, in the naive factorization model, that can be calculated by QCD factorizing models have a large impact on the branching fraction of these decay modes. The predictions of the branching fractions are of the order of 10-6. The measurement of the branching fraction gives more insight into the theoretical models. In general a better understanding of QCD models will be necessary to conduct weak interaction physics at the next level. The presence of CP violation in electroweak interactions allows the differentiation between matter and antimatter in the laws of physics. In the Standard Model, CP violation is incorporated in the CKM matrix that describes the weak interaction between quarks. Relations amongst the CKM matrix elements are used to present the two relevant parameters as the apex of a triangle (Unitarity Triangle) in a complex plane. The over-constraining of the CKM triangle by experimental measurements is an important test of the Standard Model. At this moment no stringent direct measurements of the CKM angle γ, one of the interior angles of the Unitarity Triangle, are available. The measurement of the angle γ can be performed using the decays of neutral B mesons. The B0 → D*- a0+ decay is sensitive to the angle γ and, in comparison to the current decays that are being employed, could significantly

  18. Is Radioactive Decay Really Exponential?

    OpenAIRE

    Aston, Philip J.

    2012-01-01

    Radioactive decay of an unstable isotope is widely believed to be exponential. This view is supported by experiments on rapidly decaying isotopes but is more difficult to verify for slowly decaying isotopes. The decay of 14C can be calibrated over a period of 12,550 years by comparing radiocarbon dates with dates obtained from dendrochronology. It is well known that this approach shows that radiocarbon dates of over 3,000 years are in error, which is generally attributed to past variation in ...

  19. CP-violations in B decays

    Indian Academy of Sciences (India)

    Recent results on CP-violation measurements in decays from energy asymmetric -factory experiments are reported. Thanks to large accumulated data samples, CP-violations in decays in mixing-decay interference and direct CP-violation are now firmly established. The measurements of three angles of the unitarity ...

  20. Wandering accelerators throughout my life (4)

    International Nuclear Information System (INIS)

    Nakai, Kozi

    2010-01-01

    My effort in the last stage of wandering about accelerator was to bridge the gap between nuclear and high-energy physics at the KEK-PS. Since the TRISTAN construction started, the KEK-PS has been opened to nuclear physics users. Among various possibilities, emphasis was placed on the hypernuclear experiments, K-decay experiments, and later, the long-base-line neutrino experiment (K2K), which were successfully carried out. Although the TRISTAN experiment was unable to find the top quark, the CP-test experiments at TRISTAN-II (KEKB) have proven the Kobayashi-Maskawa theory successfully. During the last three years of my tenure in KEK, I served as a science adviser to Minister of Education, and I was involved in international affairs of accelerator science. (author)

  1. High resolution spectroscopy of the 12Lambda B hypernucleus produced by the (e,e'K+) reaction.

    Science.gov (United States)

    Miyoshi, T; Sarsour, M; Yuan, L; Zhu, X; Ahmidouch, A; Ambrozewicz, P; Androic, D; Angelescu, T; Asaturyan, R; Avery, S; Baker, O K; Bertovic, I; Breuer, H; Carlini, R; Cha, J; Chrien, R; Christy, M; Cole, L; Danagoulian, S; Dehnhard, D; Elaasar, M; Empl, A; Ent, R; Fenker, H; Fujii, Y; Furic, M; Gan, L; Garrow, K; Gasparian, A; Gueye, P; Harvey, M; Hashimoto, O; Hinton, W; Hu, B; Hungerford, E; Jackson, C; Johnston, K; Juengst, H; Keppel, C; Lan, K; Liang, Y; Likhachev, V P; Liu, J H; Mack, D; Margaryan, A; Markowitz, P; Martoff, J; Mkrtchyan, H; Nakamura, S N; Petkovic, T; Reinhold, J; Roche, J; Sato, Y; Sawafta, R; Simicevic, N; Smith, G; Stepanyan, S; Tadevosyan, V; Takahashi, T; Tanida, K; Tang, L; Ukai, M; Uzzle, A; Vulcan, W; Wells, S; Wood, S; Xu, G; Yamaguchi, H; Yan, C

    2003-06-13

    High-energy, cw electron beams at new accelerator facilities allow electromagnetic production and precision study of hypernuclear structure, and we report here on the first experiment demonstrating the potential of the (e,e'K+) reaction for hypernuclear spectroscopy. This experiment is also the first to take advantage of the enhanced virtual photon flux available when electrons are scattered at approximately zero degrees. The observed energy resolution was found to be approximately 900 keV for the (12)(Lambda)B spectrum, and is substantially better than any previous hypernuclear experiment using magnetic spectrometers. The positions of the major excitations are found to be in agreement with a theoretical prediction and with a previous binding energy measurement, but additional structure is also observed in the core excited region, underlining the future promise of this technique.

  2. B decays

    CERN Document Server

    Stone, Sheldon

    1994-01-01

    This book reviews the study of b quarks and also looks at the implications of future studies. The most important observations thus far - including measurement of the ""B"" lifetime and observations of b -> u transitions - as well as the more mundane results of hadronic and semileptonic transitions are described in detail by experimentalists who have been closely involved with the measurements. Theoretical progress in understanding b quark decays, including the mechanisms of hadronic and semileptonic decays, are described. Synthesizing the experimental and theoretical information, the authors d

  3. Polarization in heavy quark decays

    Energy Technology Data Exchange (ETDEWEB)

    Alimujiang, K.

    2006-07-01

    In this thesis I concentrate on the angular correlations in top quark decays and their next.to.leading order (NLO) QCD corrections. I also discuss the leading.order (LO) angular correlations in unpolarized and polarized hyperon decays. In the first part of the thesis I calculate the angular correlation between the top quark spin and the momentum of decay products in the rest frame decay of a polarized top quark into a charged Higgs boson and a bottom quark in Two-Higgs-Doublet-Models: t({up_arrow}) {yields} b + H{sup +}. I provide closed form formulae for the O({alpha}{sub s}) radiative corrections to the unpolarized and the polar correlation functions for m{sub b}{ne}0 and m{sub b}=0. In the second part I concentrate on the semileptonic rest frame decay of a polarized top quark into a bottom quark and a lepton pair: t({up_arrow}){yields}X{sub b}+l{sup +}+{nu}{sub l}. I present closed form expressions for the O({alpha}{sub s}) radiative corrections to the unpolarized part and the polar and azimuthal correlations for m{sub b}{ne}0 and m{sub b}=0. In the last part I turn to the angular distribution in semileptonic hyperon decays. Using the helicity method I derive complete formulas for the leading order joint angular decay distributions occurring in semileptonic hyperon decays including lepton mass and polarization effects. (orig.)

  4. Effective Majorana neutrino decay

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, Lucia [Instituto de Fisica, Facultad de Ingenieria,Universidad de la Republica, Montevideo (Uruguay); Romero, Ismael; Peressutti, Javier; Sampayo, Oscar A. [Universidad Nacional de Mar del Plata, Departamento de Fisica, Instituto de Investigaciones Fisicas de Mar del Plata (IFIMAR) CONICET, UNMDP, Mar del Plata (Argentina)

    2016-08-15

    We study the decay of heavy sterile Majorana neutrinos according to the interactions obtained from an effective general theory. We describe the two- and three-body decays for a wide range of neutrino masses. The results obtained and presented in this work could be useful for the study of the production and detection of these particles in a variety of high energy physics experiments and astrophysical observations. We show in different figures the dominant branching ratios and the total decay width. (orig.)

  5. Statistical decay of giant resonances

    International Nuclear Information System (INIS)

    Dias, H.; Teruya, N.; Wolynec, E.

    1986-01-01

    Statistical calculations to predict the neutron spectrum resulting from the decay of Giant Resonances are discussed. The dependence of the resutls on the optical potential parametrization and on the level density of the residual nucleus is assessed. A Hauser-Feshbach calculation is performed for the decay of the monople giant resonance in 208 Pb using the experimental levels of 207 Pb from a recent compilation. The calculated statistical decay is in excelent agreement with recent experimental data, showing that the decay of this resonance is dominantly statistical, as predicted by continuum RPA calculations. (Author) [pt

  6. Statistical decay of giant resonances

    International Nuclear Information System (INIS)

    Dias, H.; Teruya, N.; Wolynec, E.

    1986-02-01

    Statistical calculations to predict the neutron spectrum resulting from the decay of Giant Resonances are discussed. The dependence of the results on the optical potential parametrization and on the level density of the residual nucleus is assessed. A Hauser-Feshbach calculation is performed for the decay of the monopole giant resonance in 208 Pb using the experimental levels of 207 Pb from a recent compilation. The calculated statistical decay is in excellent agreement with recent experimental data, showing that decay of this resonance is dominantly statistical, as predicted by continuum RPA calculations. (Author) [pt

  7. Three-body Supersymmetric Top Decays

    CERN Document Server

    Belyaev, A; Lola, S; Belyaev, Alexander; Ellis, John; Lola, Smaragda

    2000-01-01

    We discuss three-body supersymmetric top decays, in schemes both with andwithout R-parity conservation, assuming that sfermion masses are larger thanm_t. We find that MSSM top decays into chargino/neutralino pairs have a strongkinematic suppression in the region of the supersymmetric parameter spaceconsistent with the LEP limits, with a decay width =< 10^{-5} GeV. MSSM topdecays into neutralino pairs have less kinematical suppression, but require aflavour-changing vertex, and are likely to have a smaller rate. On the otherhand, R-violating decays to single charginos, neutralinos and conventionalfermions can be larger for values of the R-violating couplings still permittedby other upper limits. The cascade decays of the charginos and neutralinos maylead to spectacular signals with explicit lepton-number violation, such aslike-sign lepton events.

  8. Neutrinoless Double Beta Decay Experiments

    International Nuclear Information System (INIS)

    Garfagnini, A.

    2014-08-01

    Neutrinoless double beta decay is the only process known so far able to test the neutrino intrinsic nature: its experimental observation would imply that the lepton number is violated by two units and prove that neutrinos have a Majorana mass components, being their own anti-particle. While several experiments searching for such a rare decay have been per- formed in the past, a new generation of experiments using different isotopes and techniques have recently released their results or are taking data and will provide new limits, should no signal be observed, in the next few years to come. The present contribution reviews the latest public results on double beta decay searches and gives an overview on the expected sensitivities of the experiments in construction which will be able to set stronger limits in the near future. EXO and KamLAND-Zen experiments are based on the decay of Xe 136 , GERDA and MAJORANA experiments are based on the decay of Ge 76 , and the CUORE experiment is based on the decay of Te 130

  9. JEF-2.2 radioactive decay data

    International Nuclear Information System (INIS)

    1994-08-01

    This work deals with the JEF-2.2 radioactive decay data and is divided into four tables. The first table presents the origin of the JEF-2.2 radioactive decay data and subsequent modifications. The second one is a summary of the JEF-2.2 radioactive decay data file. The third one describes the JEF-2.2 fission products and the main decay and fission yield data. The last one consists of the main decay parameters from the JEF-2.2, ENDF/B-VI and JNDC-2.0 libraries. (O.L.). 100 figs., 4 tabs

  10. Feasibility study of performing high precision gamma spectroscopy of {lambda}{lambda} hypernuclei in the anti PANDA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Lorente, Alicia

    2010-09-30

    Hypernuclear research will be one of the main topics addressed by the anti PANDA experiment at the planned Facility for Antiproton and Ion Research anti FAIR. Thanks to the use of stored anti p beams, copious production of double {lambda} hypernuclei is expected at the anti PANDA experiment, which will enable high precision {gamma} spectroscopy of such nuclei for the first time. At anti PANDA excited states of {xi}{sup -} hypernuclei will be used as a basis for the formation of double {lambda} hypernuclei. For their detection, a devoted hypernuclear detector setup is planned. This setup consists of a primary nuclear target for the production of {xi}{sup -}+ anti {xi} pairs, a secondary active target for the hypernuclei formation and the identification of associated decay products and a germanium array detector to perform {gamma} spectroscopy. In the present work, the feasibility of performing high precision {gamma} spectroscopy of double {lambda} hypernuclei at the anti PANDA experiment has been studied by means of a Monte Carlo simulation. For this issue, the designing and simulation of the devoted detector setup as well as of the mechanism to produce double {lambda} hypernuclei have been optimized together with the performance of the whole system. In addition, the production yields of double hypernuclei in excitedparticle stable states have been evaluated within a statistical decay model. A strategy for the unique assignment of various newly observed {gamma}-transitions to specific double hypernuclei has been successfully implemented by combining the predicted energy spectra of each target with the measurement of two pion momenta from the subsequent weak decays of a double hypernucleus. Indeed, based on these Monte Carlo simulation, the analysis of the statistical decay of {sup 13}{sub {lambda}}{sub {lambda}}B has been performed. As result, three {gamma}-transitions associated to the double hypernuclei {sup 11}{sub {lambda}}{sub {lambda}}Be and to the single

  11. Dental Caries (Tooth Decay)

    Science.gov (United States)

    ... Materials Contact Us Home Research Data & Statistics Dental Caries (Tooth Decay) Dental caries (tooth decay) remains the most prevalent chronic disease ... adults, even though it is largely preventable. Although caries has significantly decreased for most Americans over the ...

  12. Dental Caries (Tooth Decay)

    Science.gov (United States)

    ... Contact Us Home Research Data & Statistics Share Dental Caries (Tooth Decay) Dental caries (tooth decay) remains the most prevalent chronic disease ... adults, even though it is largely preventable. Although caries has significantly decreased for most Americans over the ...

  13. Decay data evaluation project: Evaluation of 52Mn and 52mMn nuclear decay data

    Science.gov (United States)

    Luca, Aurelian

    2017-09-01

    All nuclear decay data within the 52Fe-52m,52Mn-52Cr decay chain have been evaluated at IFIN-HH, Romania, as part of an IAEA coordinated research project (F41029) and incorporated into the Decay Data Evaluation Project (DDEP). Both 52Fe and daughter 52Mn are two potentially promising radionuclides to be incorporated into suitable radiopharmaceuticals for PET and SPECT imaging. The decay data evaluation of 52Fe has previously been published and reported to the IAEA Nuclear Data Section. Equivalent DDEP evaluations for 52Mn and 52mMn have also been completed recently, and are presented in summary form below. These improved decay data sets have also been reported to the IAEA in detail, and are highly suitable in dose rate calculations for their application in nuclear medicine.

  14. Weak radiative hyperon decays

    International Nuclear Information System (INIS)

    Roberts, B.L.; Booth, E.C.; Gall, K.P.; McIntyre, E.K.; Miller, J.P.; Whitehouse, D.A.; Bassalleck, B.; Hall, J.R.; Larson, K.D.; Wolfe, D.M.; Fickinger, W.J.; Robinson, D.K.; Hallin, A.L.; Hasinoff, M.D.; Measday, D.F.; Noble, A.J.; Waltham, C.E.; Hessey, N.P.; Lowe, J.; Horvath, D.; Salomon, M.

    1990-01-01

    New measurements of the Σ + and Λ weak radiative decays are discussed. The hyperons were produced at rest by the reaction K - p → Yπ where Y = Σ + or Λ. The monoenergetic pion was used to tag the hyperon production, and the branching ratios were determined from the relative amplitudes of Σ + → pγ to Σ + → pπ 0 and Λ → nγ to Λ → nπ 0 . The photons from weak radiative decays and from π 0 decays were detected with modular NaI arrays. (orig.)

  15. Rare decays of B-mesons

    International Nuclear Information System (INIS)

    Ali, A.

    1991-07-01

    This paper is organized as follows. First, we discuss the decay rates for b → (s,d) + γ in the lowest order (1 loop) and including the QCD corrections in the effective Hamiltonian method. The photon energy spectrum in the inclusive decays B → X s + γ is evaluated in this approach and the dominant background from the CC decays B → X c + γ is presented. Next, we discuss the calculations for the inclusive decays b → s + anti l (l = e,μ,ν), including the QCD corrections. Finally, we summarize rate estimates for the exclusive rare decays of the B-meson, B → K*γ, and B → (K,K*) anti l (l = e,μ,ν), as well as B o s,d → γγ and B o s,d → l + l - with (l = e,μ,r). (orig./HSI)

  16. The β-decay Paul trap: A radiofrequency-quadrupole ion trap for precision β-decay studies

    International Nuclear Information System (INIS)

    Scielzo, N.D.; Li, G.; Sternberg, M.G.; Savard, G.; Bertone, P.F.; Buchinger, F.; Caldwell, S.; Clark, J.A.; Crawford, J.; Deibel, C.M.; Fallis, J.; Greene, J.P.

    2012-01-01

    The β-decay Paul trap is a linear radiofrequency-quadrupole ion trap that has been developed for precision β-decay studies. The design of the trap electrodes allows a variety of radiation detectors to surround the cloud of trapped ions. The momentum of the low-energy recoiling daughter nuclei following β decay is negligibly perturbed by scattering and is available for study. This advantageous property of traps allows the kinematics of particles that are difficult or even impossible to directly detect to be precisely reconstructed using conservation of energy and momentum. An ion-trap system offers several advantages over atom traps, such as higher trapping efficiencies and element-independent capabilities. The first precision experiment using this system is a measurement of β-decay angular correlations in the decay of 8 Li performed by inferring the momentum of the neutrino from the kinematic shifts imparted to the breakup α particles. Many other β-decay studies that would benefit from a determination of the nuclear recoil can be performed with this system.

  17. The {beta}-decay Paul trap: A radiofrequency-quadrupole ion trap for precision {beta}-decay studies

    Energy Technology Data Exchange (ETDEWEB)

    Scielzo, N.D., E-mail: scielzo1@llnl.gov [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Li, G. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8 (Canada); Sternberg, M.G.; Savard, G. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, University of Chicago, Chicago, Illinois 60637 (United States); Bertone, P.F. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Buchinger, F. [Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8 (Canada); Caldwell, S. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, University of Chicago, Chicago, Illinois 60637 (United States); Clark, J.A. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Crawford, J. [Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8 (Canada); Deibel, C.M. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824 (United States); Fallis, J. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2 (Canada); Greene, J.P. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); and others

    2012-07-21

    The {beta}-decay Paul trap is a linear radiofrequency-quadrupole ion trap that has been developed for precision {beta}-decay studies. The design of the trap electrodes allows a variety of radiation detectors to surround the cloud of trapped ions. The momentum of the low-energy recoiling daughter nuclei following {beta} decay is negligibly perturbed by scattering and is available for study. This advantageous property of traps allows the kinematics of particles that are difficult or even impossible to directly detect to be precisely reconstructed using conservation of energy and momentum. An ion-trap system offers several advantages over atom traps, such as higher trapping efficiencies and element-independent capabilities. The first precision experiment using this system is a measurement of {beta}-decay angular correlations in the decay of {sup 8}Li performed by inferring the momentum of the neutrino from the kinematic shifts imparted to the breakup {alpha} particles. Many other {beta}-decay studies that would benefit from a determination of the nuclear recoil can be performed with this system.

  18. Induced nuclear beta decay

    International Nuclear Information System (INIS)

    Reiss, H.R.

    1986-01-01

    Certain nuclear beta decay transitions normally inhibited by angular momentum or parity considerations can be induced to occur by the application of an electromagnetic field. Such decays can be useful in the controlled production of power, and in fission waste disposal

  19. Three-body charmless B decays workshop

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Haim, E.; Chauveau, J.; Hartfiel, B.; Ocariz, J. [Laboratoire de Physique Nucleaire et de Hautes Energies (LPNHE), 75 - Paris (France); Charles, J. [LPT, 13 - Marseille (France)

    2006-07-01

    The purpose of this workshop was multifarious: -) to present and discuss the current experimental perspectives based on the full expected statistics from B-factories by 2008, -) to share and further develop analysis methods, -) to present and discuss the theoretical work on the subject, -) to discuss the future of B-factories, and -) to establish a work plan until 2009. The contributions have focused on 3 body charmless B decays and mostly 3 body hadronic charmless B decays, they have also dealt with semileptonic decays, radiative decays, charm and charmonium decays, and scattering processes. This document gathers the slides of the presentations.

  20. Constraints on hadronically decaying dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Garny, Mathias [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ibarra, Alejandro [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Tran, David [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Minnesota Univ., Minneapolis, MN (United States). School of Physics and Astronomy

    2012-05-15

    We present general constraints on dark matter stability in hadronic decay channels derived from measurements of cosmic-ray antiprotons.We analyze various hadronic decay modes in a model-independent manner by examining the lowest-order decays allowed by gauge and Lorentz invariance for scalar and fermionic dark matter particles and present the corresponding lower bounds on the partial decay lifetimes in those channels. We also investigate the complementarity between hadronic and gamma-ray constraints derived from searches for monochromatic lines in the sky, which can be produced at the quantum level if the dark matter decays into quark-antiquark pairs at leading order.

  1. Three-body charmless B decays workshop

    International Nuclear Information System (INIS)

    Ben-Haim, E.; Chauveau, J.; Hartfiel, B.; Ocariz, J.; Charles, J.

    2006-01-01

    The purpose of this workshop was multifarious: -) to present and discuss the current experimental perspectives based on the full expected statistics from B-factories by 2008, -) to share and further develop analysis methods, -) to present and discuss the theoretical work on the subject, -) to discuss the future of B-factories, and -) to establish a work plan until 2009. The contributions have focused on 3 body charmless B decays and mostly 3 body hadronic charmless B decays, they have also dealt with semileptonic decays, radiative decays, charm and charmonium decays, and scattering processes. This document gathers the slides of the presentations

  2. Constraints on hadronically decaying dark matter

    International Nuclear Information System (INIS)

    Garny, Mathias; Ibarra, Alejandro; Tran, David; Minnesota Univ., Minneapolis, MN

    2012-05-01

    We present general constraints on dark matter stability in hadronic decay channels derived from measurements of cosmic-ray antiprotons.We analyze various hadronic decay modes in a model-independent manner by examining the lowest-order decays allowed by gauge and Lorentz invariance for scalar and fermionic dark matter particles and present the corresponding lower bounds on the partial decay lifetimes in those channels. We also investigate the complementarity between hadronic and gamma-ray constraints derived from searches for monochromatic lines in the sky, which can be produced at the quantum level if the dark matter decays into quark-antiquark pairs at leading order.

  3. Search for new mechanism of CP violation through decay of leptons and semileptonic decay of hadrons

    International Nuclear Information System (INIS)

    Tsai, Y.S.

    1996-11-01

    If CP is violated in any decay process involving leptons it will signify the existence of a new scalar boson (called the X boson) responsible for CP violation that may be the key to understanding matter-antimatter asymmetry in the universe. The authors discuss the signatures of CP violation in (1) the decay of tau and mu leptons, and (2) the semileptonic decay of π, K, D, B and t particles by measuring the polarization of the charged lepton in the decay. The authors discuss how the coupling constants and their phases of the coupling of the X boson to 9 quark vertices and 3 lepton vertices can be obtained through 12 decay processes

  4. B decays

    CERN Document Server

    Stone, Sheldon

    1992-01-01

    The study of b quarks has now reached a stage where it is useful to review what has been learned so far and also to look at the implications of future studies. The most important observations thus far - measurement of the "B" lifetime, B 0 - B 0 mixing, and the observation of b? u transitions, as well as more mundane results on hadronic and semileptonic transitions - are described in detail by experimentalists who have been closely involved with the measurements. Theoretical progress in understanding b quark decays, including the mechanisms of hadronic and semileptonic decays, are described. S

  5. Weak decays of heavy quarks

    International Nuclear Information System (INIS)

    Gaillard, M.K.

    1978-08-01

    The properties that may help to identify the two additional quark flavors that are expected to be discovered. These properties are lifetime, branching ratios, selection rules, and lepton decay spectra. It is also noted that CP violation may manifest itself more strongly in heavy particle decays than elsewhere providing a new probe of its origin. The theoretical progress in the understanding of nonleptonic transitions among lighter quarks, nonleptonic K and hyperon decay amplitudes, omega minus and charmed particle decay predictions, and lastly the Kobayashi--Maskawa model for the weak coupling of heavy quarks together with the details of its implications for topology and bottomology are treated. 48 references

  6. Evidence of interatomic Coulombic decay in ArKr after Ar 2p Auger decay

    International Nuclear Information System (INIS)

    Morishita, Y; Saito, N; Suzuki, I H; Fukuzawa, H; Liu, X-J; Sakai, K; Pruemper, G; Ueda, K; Iwayama, H; Nagaya, K; Yao, M; Kreidi, K; Schoeffler, M; Jahnke, T; Schoessler, S; Doerner, R; Weber, T; Harries, J; Tamenori, Y

    2008-01-01

    We have identified interatomic Coulombic decay (ICD) processes in the ArKr dimer following Ar 2p Auger decay, using momentum-resolved electron-ion-ion coincidence spectroscopy and simultaneously determining the kinetic energy of the ICD electron and the KER between Ar 2+ and Kr + . We find that the spin-conserved ICD processes in which Ar 2+ (3p -3 3d) 1 P and 3 P decay to Ar 2+ (3p -2 ) 1 D and 3 P, respectively, ionizing the Kr atom, are significantly stronger than the spin-flip ICD processes in which Ar 2+ (3p -3 3d) 1 P and 3 P decay to Ar 2+ (3p -2 ) 3 P and 1 D, respectively

  7. The Decay Data Evaluation Project (DDEP) and the JEFF-3.3 radioactive decay data library: Combining international collaborative efforts on evaluated decay data

    Science.gov (United States)

    Kellett, Mark A.; Bersillon, Olivier

    2017-09-01

    The Decay Data Evaluation Project (DDEP), is an international collaboration of decay data evaluators formed with groups from France, Germany, USA, China, Romania, Russia, Spain and the UK, mainly from the metrology community. DDEP members have evaluated over 220 radionuclides, following an agreed upon methodology, including a peer review. Evaluations include all relevant parameters relating to the nuclear decay and the associated atomic processes. An important output of these evaluations are recommendations for new measurements, which can serve as a basis for future measurement programmes. Recently evaluated radionuclides include: 18F, 59Fe, 82Rb, 82Sr, 88Y, 90Y, 89Zr, 94mTc, 109Cd, 133Ba, 140Ba, 140La, 151Sm and 169Er. The DDEP recommended data have recently been incorporated into the JEFF-3.3 Radioactive Decay Data Library. Other sources of nuclear data include 900 or so radionuclides converted from the Evaluated Nuclear Structure Data File (ENSDF), 500 from two UK libraries (UKPADD6.12 and UKHEDD2.6), the IAEA Actinide Decay Data Library, with the remainder converted from the NUBASE evaluation of nuclear properties. Mean decay energies for a number of radionuclides determined from total absorption gamma-ray spectroscopy (TAGS) have also been included, as well as more recent European results from TAGS measurements performed at the University of Jyväskylä by groups from the University of Valencia, Spain and SUBATECH, the University of Nantes, France. The current status of the DDEP collaboration and the JEFF Radioactive Decay Data Library will be presented. Note to the reader: the pdf file has been changed on September 22, 2017.

  8. CP violation in rare K decays

    International Nuclear Information System (INIS)

    Ecker, G.

    1990-01-01

    The investigation of rare K decays calls for a unified treatment of short- and long-distance aspects as provided by chiral perturbation theory. For the standard model with three generations, the theoretical predictions for signals of CP violation in those decays are reviewed. With direct CP violation as the main target, special emphasis is given to the charge asymmetries in charged K decays and to the especially rare decays K L → π 0 ll-bar. Time dependent rate asymmetries in K 0 decays and the longitudinal muon polarization in K L → μ + μ - are also discussed. 50 refs., 3 figs., 1 tab. (Author)

  9. B decays to baryons

    Indian Academy of Sciences (India)

    We note that two-body decays to baryons are suppressed relative to three- and four-body decays. In most of these analyses, the invariant baryon–antibaryon mass shows an enhancement near the threshold. We propose a phenomenological interpretation of this quite common feature of hadronization to baryons.

  10. Fine structure of cluster decays

    International Nuclear Information System (INIS)

    Dumitrescu, O.

    1993-07-01

    Within the one level R-matrix approach the hindrance factors of the radioactive decays in which are emitted α and 14 C - nuclei are calculated. The generalization to radioactive decays in which are emitted heavier clusters such as e.g. 20 O, 24 Ne, 25 Ne, 28 Mg. 30 Mg, 32 Si and 34 Si is straightforward. The interior wave functions are supposed to be given by the shell model with effective residual interactions (e.g. the large scale shell model code-OXBASH - in the Michigan State University version for nearly spherical nuclei or by the enlarged superfluid model - ESM - recently proposed for deformed nuclei). The exterior wave functions are calculated from a cluster - nucleus double - folding model potential obtained with the M3Y interaction. As examples of the cluster decay fine structure we analyzed the particular cases of α - decay of 241 Am and 14 C -decay of 233 Ra. Good agreement with the experimental data is obtained. (author). 78 refs, 2 figs, 6 tabs

  11. Rare beauty and charm decays

    International Nuclear Information System (INIS)

    Blake, T.

    2016-01-01

    Rare beauty and charm decays can provide powerful probes of physics beyond the Standard Model. These proceedings summarise the latest measurements of rare beauty and charm decays from the LHCb experiment at the end of Run 1 of the LHC. Whilst the majority of the measurements are consistent with SM predictions, small differences are seen in the rate and angular distribution of b → sℓ"+ℓ"− decay processes.

  12. Study of charmonium rare decays

    International Nuclear Information System (INIS)

    Brient, J.C.

    1986-09-01

    This thesis presents the study of rare decays of charmonium states formed in the interaction of an antiproton beam with an hydrogen gas jet target. Electromagnetic final states are used to sign the charmonium state formation (e + e - , e + e - + Χ, γγ). The selection of events used a two arms non magnetic spectrometer, with a charged track system, a threshold Cerenkov counter to tag the electron (positron), and an e.m. calorimeter. Energy scan technic have been used to observe the resonant formation through the excitation curves. Parameters of the states (mass, total and partial widths) are extracted from these curves using a statistical analysis. Two types of decays have been studied in this thesis: 1 P 1 charmonium state decay to the ψ (signed by its e + e - decay). In the energy scan around the center of gravity of the P charmonium states, we observe a cluster of 5 events, in a narrow mass range. This cluster correspond to a 2.7 σ signal. The most probable interpretation of this signal is given by a narrow resonance, with a mass of 3526. MeV. Due to the properties (mass, width and decay) of this signal, this could be interpreted as the 1 P 1 charmonium state. 2 photons decay of the η c and Χ 2 . 22 γγ events are observed, 15 in the η c region, and 7 in the Χ 2 region. This sample is interpreted as a direct observation of η c and Χ 2 decay into γγ. Parameters of these decays, (γγ partial width), are extracted using a maximum likekihood analysis. Theoretical models of charmonium explain correctly the properties of the charmonium, including the results presented in this thesis. 57 refs [fr

  13. Beta decay and rhenium cosmochronology

    International Nuclear Information System (INIS)

    Ashktorab, K.

    1992-01-01

    Among the problems which limit the use of the 187 Re/ 187 Os isobaric pair as a cosmochronometer for the age of the galaxy and the universe are the uncertainties in the partial half-lives of the continuum and bound state decays of 187 Re. While the total half-life of the decay is well established, the partial half-life for the continuum decay is uncertain, and several measurements are not compatible. A high temperature quartz proportional counter was used in this work to remeasure the continuum β - decay of 187 Re. The β endpoint energy for the decay of neutral 187 Re to singly ionized 187 Os of 2.75 ± 0.06 keV agrees with the earlier results. The corresponding half-life of (45 ± 3) x 10 9 years improves and agrees with the earlier measurement of Payne and Drever and refutes other measurements. Based on the new half-life for the continuum decay and a total half-life of (43.5 ± 1.3) x 10 9 years reported by Linder et al., the branching ratio for the bound state decay into discrete atomic states is estimated to be (3 ± 6)% in agreement with the most recent calculated theoretical branching ratio of approximately 1%. Anomalies in beta spectra reported by J.J. Simpson and others have been attributed to a 17 keV heavy-neutrino admixture. If confirmed, the implications from the existence of such a neutrino for particle and astrophysics would be significant. A multiwire open-quotes wall-lessclose quotes stainless steel proportional counter has been used in the present work to investigate the spectral shape of the β decay of 63 Ni. No anomalies in the spectral shape were observed which could be attributed to the presence of 17 keV heavy neutrino

  14. On t-quark decay

    International Nuclear Information System (INIS)

    Chizhov, M.V.

    1995-07-01

    An extended electroweak model with second rank antisymmetric tensor field is proposed. The effective interactions resulting from the exchange of these fields have specific dependence on the transfer momentum. This leads to the introduction of new model-independent muon decay parameters (Mod. Phys. Lett. A9 (1994) 2979), which can be measured experimentally in SLAC and TRIUMF. The new tensor interactions can effect the three-particles semileptonic meson decays (Mod. Phys. Lett. A8 (1993) 2753). In this connection it will be interesting to propose new experiments on K + → l + νγ, K + → π 0 l + ν decays in DAΦNE. The K L -K s mass difference sets constraints on the tensor particles masses. The mass of the lightest tensor particle could be less than the t-quark mass. Therefore the lightest tensor particle may give an additional to the W-boson contribution into the t- quark decay with the same signature. (author). 10 refs, 2 figs

  15. Black hole decay as geodesic motion

    International Nuclear Information System (INIS)

    Gupta, Kumar S.; Sen, Siddhartha

    2003-01-01

    We show that a formalism for analyzing the near-horizon conformal symmetry of Schwarzschild black holes using a scalar field probe is capable of describing black hole decay. The equation governing black hole decay can be identified as the geodesic equation in the space of black hole masses. This provides a novel geometric interpretation for the decay of black holes. Moreover, this approach predicts a precise correction term to the usual expression for the decay rate of black holes

  16. Three-Phased Wake Vortex Decay

    Science.gov (United States)

    Proctor, Fred H.; Ahmad, Nashat N.; Switzer, George S.; LimonDuparcmeur, Fanny M.

    2010-01-01

    A detailed parametric study is conducted that examines vortex decay within turbulent and stratified atmospheres. The study uses a large eddy simulation model to simulate the out-of-ground effect behavior of wake vortices due to their interaction with atmospheric turbulence and thermal stratification. This paper presents results from a parametric investigation and suggests improvements for existing fast-time wake prediction models. This paper also describes a three-phased decay for wake vortices. The third phase is characterized by a relatively slow rate of circulation decay, and is associated with the ringvortex stage that occurs following vortex linking. The three-phased decay is most prevalent for wakes imbedded within environments having low-turbulence and near-neutral stratification.

  17. Rare KL decays at Fermilab

    International Nuclear Information System (INIS)

    Schnetzer, St.

    1997-01-01

    Recent results and the future prospects for rare K L decay at Fermilab are described. A summary of all rare decay results from E799 Phase I (the 1991 run) are presented. Three new results: K L → e + e - μ + μ - , K L → π 0 μe, and π 0 → e + e - e + e - are discussed in detail. Improvements for KTeV (the 1996-1997 run) are discussed and the expected sensitivities listed. Finally, the KAMI program for rare decays with the Main Injector (2000 and beyond) is presented with emphasis on a search for the decay K L → π 0 νν-bar at O(10 -12 ) single-event-sensitivity. (author)

  18. Is neutrinoless double beta decay suppressed

    International Nuclear Information System (INIS)

    Tomoda, T.

    1989-01-01

    Much effort has been devoted to the study of nuclear double beta decay, since the observation of a neutrinoless double beta (OνΒΒ) decay would be clear evidence that the electron neutrino is a Majorana particle. The OνΒΒ decay is caused by a finite Majorana neutrino mass and/or an admixture of right-handed leptonic currents. In order to relate these quantities to OνΒΒ decay rates, we need nuclear matrix elements, which are model dependent. One of the possibilities of testing nuclear models employed in such analysis is to calculate the experimentally known rates of ΒΒ decay with emission of two neutrinos (2νΒΒ decay) which occurs independently of the nature of the neutrino. There was a long-standing difficulty in such attempts that the calculated 2νΒΒ decay rates turned out to be always too large by one to two orders of magnitude. Trying to overcome such difficulty, Klapdor and Grotz as well as Vogel and Zirnbauer showed in their calculation using schematic effective interactions such that 2νΒΒ decay rates can get reduced considerably due to the nuclear ground state correlations. This paper reports that the suppression is ascribed to that of the virtual Gamow-Teller transitions from the excited 1 + states of the intermediate odd-odd -even nucleus

  19. Development of limiting decay heat values

    International Nuclear Information System (INIS)

    Khotylev, V.A.; Thompson, J.W.; Gibb, R.A.

    1999-01-01

    A number of tools are used in the assessment of decay heat during an outage of the CANDU-6. Currently, the technical basis for all of these tools is 'CANDU Channel Decay Power', Reference 1. The methods used in that document were limited to channel decay powers. However, for most outage support analysis, decay heat limits are based on bundle heats. Since the production of that document in 1977, new versions of codes, and updates of general-purpose and CANDU-specific libraries have become available. These tools and libraries have both a more formal technical basis than Reference 1, and also a more formal validation base. Using these tools it is now possible to derive decay heat with more specific input parameters, such as fuel composition, heat per unit of fuel, and irradiation history, and to assign systematically derived uncertainty allowances to such decay heat values. In particular, we sought to examine a broad range of likely bundle histories, and thus establish a set of limiting bundle decay beat values, that could serve as a bounding envelope for use in Nuclear Safety Analysis. (author)

  20. Multiple photon emission in heavy particle decays

    International Nuclear Information System (INIS)

    Asakimori, K.; Burnett, T.H.; Cherry, M.L.

    1994-03-01

    Cosmic ray interactions, at energies above 1 TeV/nucleon, in emulsion chambers flown on high altitude balloons have yielded two events showing apparent decays of a heavy particle into one charged particle and four photons. The photons converted into electron pairs very close to the decay vertex. Attempts to explain this decay topology with known particle decays are presented. Unless both events represent a b → u transition, which is statistically unlikely, then other known decay modes for charmed or bottom particles do not account satisfactorily for these observations. This could indicate, possibly, a new decay channel. (author). 7 refs, 6 figs, 2 tabs

  1. The decay width of stringy hadrons

    Directory of Open Access Journals (Sweden)

    Jacob Sonnenschein

    2018-02-01

    We fit the theoretical decay width to experimental data for mesons on the trajectories of ρ, ω, π, η, K⁎, ϕ, D, and Ds⁎, and of the baryons N, Δ, Λ, and Σ. We examine both the linearity in L and the exponential suppression factor. The linearity was found to agree with the data well for mesons but less for baryons. The extracted coefficient for mesons A=0.095±0.015 is indeed quite universal. The exponential suppression was applied to both strong and radiative decays. We discuss the relation with string fragmentation and jet formation. We extract the quark–diquark structure of baryons from their decays. A stringy mechanism for Zweig suppressed decays of quarkonia is proposed and is shown to reproduce the decay width of ϒ states. The dependence of the width on spin and flavor symmetry is discussed. We further apply this model to the decays of glueballs and exotic hadrons.

  2. Complex degradation processes lead to non-exponential decay patterns and age-dependent decay rates of messenger RNA.

    Directory of Open Access Journals (Sweden)

    Carlus Deneke

    Full Text Available Experimental studies on mRNA stability have established several, qualitatively distinct decay patterns for the amount of mRNA within the living cell. Furthermore, a variety of different and complex biochemical pathways for mRNA degradation have been identified. The central aim of this paper is to bring together both the experimental evidence about the decay patterns and the biochemical knowledge about the multi-step nature of mRNA degradation in a coherent mathematical theory. We first introduce a mathematical relationship between the mRNA decay pattern and the lifetime distribution of individual mRNA molecules. This relationship reveals that the mRNA decay patterns at steady state expression level must obey a general convexity condition, which applies to any degradation mechanism. Next, we develop a theory, formulated as a Markov chain model, that recapitulates some aspects of the multi-step nature of mRNA degradation. We apply our theory to experimental data for yeast and explicitly derive the lifetime distribution of the corresponding mRNAs. Thereby, we show how to extract single-molecule properties of an mRNA, such as the age-dependent decay rate and the residual lifetime. Finally, we analyze the decay patterns of the whole translatome of yeast cells and show that yeast mRNAs can be grouped into three broad classes that exhibit three distinct decay patterns. This paper provides both a method to accurately analyze non-exponential mRNA decay patterns and a tool to validate different models of degradation using decay data.

  3. On the decay of homogeneous isotropic turbulence

    Science.gov (United States)

    Skrbek, L.; Stalp, Steven R.

    2000-08-01

    Decaying homogeneous, isotropic turbulence is investigated using a phenomenological model based on the three-dimensional turbulent energy spectra. We generalize the approach first used by Comte-Bellot and Corrsin [J. Fluid Mech. 25, 657 (1966)] and revised by Saffman [J. Fluid Mech. 27, 581 (1967); Phys. Fluids 10, 1349 (1967)]. At small wave numbers we assume the spectral energy is proportional to the wave number to an arbitrary power. The specific case of power 2, which follows from the Saffman invariant, is discussed in detail and is later shown to best describe experimental data. For the spectral energy density in the inertial range we apply both the Kolmogorov -5/3 law, E(k)=Cɛ2/3k-5/3, and the refined Kolmogorov law by taking into account intermittency. We show that intermittency affects the energy decay mainly by shifting the position of the virtual origin rather than altering the power law of the energy decay. Additionally, the spectrum is naturally truncated due to the size of the wind tunnel test section, as eddies larger than the physical size of the system cannot exist. We discuss effects associated with the energy-containing length scale saturating at the size of the test section and predict a change in the power law decay of both energy and vorticity. To incorporate viscous corrections to the model, we truncate the spectrum at an effective Kolmogorov wave number kη=γ(ɛ/v3)1/4, where γ is a dimensionless parameter of order unity. We show that as the turbulence decays, viscous corrections gradually become more important and a simple power law can no longer describe the decay. We discuss the final period of decay within the framework of our model, and show that care must be taken to distinguish between the final period of decay and the change of the character of decay due to the saturation of the energy containing length scale. The model is applied to a number of experiments on decaying turbulence. These include the downstream decay of turbulence in

  4. 7 CFR 51.490 - Decay.

    Science.gov (United States)

    2010-01-01

    ... FRESH FRUITS, VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Grades of Cantaloups 1 Definitions § 51.490 Decay. Decay means breakdown, disintegration or...

  5. D meson hadronic decays at CLEO-c

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Fan; /Fermilab

    2011-01-01

    The recent CLEO-c results on hadronic decays of D and D{sub s} mesons are presented. First the absolute branching fractions for D and D{sub s} mesons using a double tag technique are discussed, then are the Cabibbo suppressed decays and doubly Cabibbo suppressed decays. Finally, I present the inclusive and rare decay modes and other measurements from CLEO-c. These decays illuminate a wide range of physics. A brief theoretical introduction is given before the corresponding discussion on measurement.

  6. CP-violation in B-decays and B-decay properties at ATLAS experiment

    CERN Document Server

    Smizanska, Maria; The ATLAS collaboration

    2015-01-01

    ATLAS has a wide programme to study the production cross section and decay properties of particles with beauty, as well as charmonium and bottomonium states. The main part of the talk will discuss the ATLAS full Run-1 analysis of mixing and CP violation in the decay of Bs meson to J/psi Phi, observed in the final state mu+mu-K+K-. The different amplitudes contributing to the process are studied through the time dependence of the angular distribution, and the average lifetime and lifetime difference between the two eigenstate BH and BL, and of the CP violating phase phi_s are extracted. The presentation will also cover selected latest ATLAS studies in the field of B-hadron decay properties.

  7. Performance studies of the P barANDA planar GEM-tracking detector in physics simulations

    Science.gov (United States)

    Divani Veis, Nazila; Firoozabadi, Mohammad M.; Karabowicz, Radoslaw; Maas, Frank; Saito, Takehiko R.; Voss, Bernd; ̅PANDA Gem-Tracker Subgroup

    2018-03-01

    The P barANDA experiment will be installed at the future facility for antiproton and ion research (FAIR) in Darmstadt, Germany, to study events from the annihilation of protons and antiprotons. The P barANDA detectors can cover a wide physics program about baryon spectroscopy and nucleon structure as well as the study of hadrons and hypernuclear physics including the study of excited hyperon states. One very specific feature of most hyperon ground states is the long decay length of several centimeters in the forward direction. The central tracking detectors of the P barANDA setup are not sufficiently optimized for these long decay lengths. Therefore, using a set of the planar GEM-tracking detectors in the forward region of interest can improve the results in the hyperon physics-benchmark channel. The current conceptual designed P barANDA GEM-tracking stations contribute the measurement of the particles emitted in the polar angles between about 2 to 22 degrees. For this designed detector performance and acceptance, studies have been performed using one of the important hyperonic decay channel p bar p → Λ bar Λ → p bar pπ+π- in physics simulations. The simulations were carried out using the PandaRoot software packages based on the FairRoot framework.

  8. CP violation in B decays

    International Nuclear Information System (INIS)

    Kayser, B.

    1990-01-01

    The study of CP-violating effects in B decays will be a good test of whether CP violation is caused by the known weak interaction. If this is its origin, then large, cleanly-predicted CP-violating effects are expected in certain neutral B decays to hadronic CP eigenstates. The phenomenology of CP violation in the B system is reviewed, and the genesis of these large effects is explained. In this it is shown that large, cleanly-predicted effects are also expected in some decays to states which are not CP eigenstates. The combined study of the latter decays and those to CP eigenstates may make it possible to obtain a statistically-significant CP-violating signal with fewer B mesons that would otherwise be required

  9. Searching for displaced Higgs boson decays

    Science.gov (United States)

    Csáki, Csaba; Kuflik, Eric; Lombardo, Salvator; Slone, Oren

    2015-10-01

    We study a simplified model of the Standard Model (SM) Higgs boson decaying to a degenerate pair of scalars which travel a macroscopic distance before decaying to SM particles. This is the leading signal for many well-motivated solutions to the hierarchy problem that do not propose additional light colored particles. Bounds for displaced Higgs boson decays below 10 cm are found by recasting existing tracker searches from Run I. New tracker search strategies, sensitive to the characteristics of these models and similar decays, are proposed with sensitivities projected for Run II at √{s }=13 TeV . With 20 fb-1 of data, we find that Higgs branching ratios down to 2 ×1 0-4 can be probed for centimeter decay lengths.

  10. Search for proton decay: introduction

    International Nuclear Information System (INIS)

    Goldhaber, M.

    1984-01-01

    In interpreting contained events observed in various proton decay detectors one can sometimes postulate, though usually not unambiguously, a potential decay mode of the proton, called a candidate. It is called a candidate, because for any individual event it is not possible to exclude the possibility that it is instead due to cosmic ray background, chiefly atmospheric neutrinos. Some consistency checks are proposed which could help establish proton decay, if it does occur in the presently accessible lifetime window

  11. Radiative decays of B mesons at LHCb

    CERN Document Server

    Soomro, Fatima; Golutvin, Andrei

    2011-01-01

    This thesis is dedicated to the study of radiative decays of $B$ mesons at LHC$b$. At quark level, such decays are a $b\\to s\\gamma$ transition and take place via a penguin loop and are sensitive to virtual contribution of New Physics, which can be indicated by an increase in the decay rates. These decays also offer the possibility to test the V-A structure of the Standard Model coupling in the processes mediated by loop penguin diagrams. In the decay $B_s \\to \\phi\\gamma$, New Physics contribution can be probed by measuring the polarization of the photon in this decay. Systematic effects in the proper time reconstruction of the $B_s$ in $B_s \\to \\phi\\gamma$ can bias the photon polarization measurement in this decay, which will reduce the sensitivity on the relevant New Physics parameter. The author studied those effects and developed ideas to calibrate them using $B_d\\to K^{*}\\gamma$ and $B_s\\to J/\\psi\\phi$ decays as control channels. These studies are mostly Monte Carlo based due to a relatively small data ...

  12. Vacancy decay in endohedral atoms

    International Nuclear Information System (INIS)

    Amusia, M. Ya.; Baltenkov, A. S.

    2006-01-01

    It is demonstrated that the fullerene shell dramatically affects the radiative and Auger vacancy decay of an endohedral atom A-C 60 . The collectivized electrons of the C 60 shell add new possibilities for radiative and nonradiative decays similar to that in ordinary atoms where the vacancies in the initial and final state almost always belong to different subshells. It is shown that the smallness of the atomic shell radii as compared to that of the fullerene shell provides an opportunity to derive the simple formulas for the probabilities of the electron transitions. It is shown that the radiative and Auger (or Koster-Kronig) widths of the vacancy decay due to electron transition in the atom A in A-C 60 acquire an additional factor that can be expressed via the polarizability of the C 60 at transition energy. It is demonstrated that due to an opening of the nonradiative decay channel for vacancies in subvalent subshells the decay probability increases by five to six orders of magnitude

  13. CRBRP decay heat removal systems

    International Nuclear Information System (INIS)

    Hottel, R.E.; Louison, R.; Boardman, C.E.; Kiley, M.J.

    1977-01-01

    The Decay Heat Removal Systems for the Clinch River Breeder Reactor Plant (CRBRP) are designed to adequately remove sensible and decay heat from the reactor following normal shutdown, operational occurrences, and postulated accidents on both a short term and a long term basis. The Decay Heat Removal Systems are composed of the Main Heat Transport System, the Main Condenser and Feedwater System, the Steam Generator Auxiliary Heat Removal System (SGAHRS), and the Direct Heat Removal Service (DHRS). The overall design of the CRBRP Decay Heat Removal Systems and the operation under normal and off-normal conditions is examined. The redundancies of the system design, such as the four decay heat removal paths, the emergency diesel power supplies, and the auxiliary feedwater pumps, and the diversities of the design such as forced circulation/natural circulation and AC Power/DC Power are presented. In addition to overall design and system capabilities, the detailed designs for the Protected Air Cooled Condensers (PACC) and the Air Blast Heat Exchangers (ABHX) are presented

  14. Decay modes of two repulsively interacting bosons

    International Nuclear Information System (INIS)

    Kim, Sungyun; Brand, Joachim

    2011-01-01

    We study the decay of two repulsively interacting bosons tunnelling through a delta potential barrier by a direct numerical solution of the time-dependent Schroedinger equation. The solutions are analysed according to the regions of particle presence: both particles inside the trap (in-in), one particle in and one particle out (in-out) and both particles outside (out-out). It is shown that the in-in probability is dominated by the exponential decay, and its decay rate is predicted very well from outgoing boundary conditions. Up to a certain range of interaction strength, the decay of in-out probability is dominated by the single-particle decay mode. The decay mechanisms are adequately described by simple models.

  15. Charmed-B decays at BaBar

    International Nuclear Information System (INIS)

    Tisserand, Vincent

    2004-01-01

    We present recent results on charmed-B decays using data collected by the BaBaR experiment at the PEP-II storage ring. This report is subdivided in 3 parts. In a first step, we present preliminary results on the measurement of the branching fractions of seven color-suppressed anti B 0 -meson decays into D (*)0 π 0 , D (*)0 η, D (*)0 ω, and D 0 η ' . Then we discuss the preliminary measurement of the ratio of Cabibbo-suppressed to Cabibbo-favored branching fractions B(B - →D 0 K - )/B(B - →D 0 π - ), where the D 0 is possibly reconstructed in the CP-even π - π + and K - K + modes. For the D 0 decays into CP-eigenstates, a search for a direct CP asymmetry is performed. For the same category of decay processes, we show a precise preliminary measurement of both the branching fraction of B - decaying to D *0 K *- and of the fraction of longitudinal polarization in this decay. Finally, we present a study where the 22 possible B decays to anti D (*) D * K are reconstructed exclusively. The branching fractions of the anti B 0 and of the B + to anti D (*) D (*) K are presented and a search for decays B→anti D (*) D sJ + (→D (*)0 K + ), where the D sJ + represents the orbitally excited D s states, is also discussed. (orig.)

  16. Rare B decays at LEP

    CERN Document Server

    Kluit, P M

    2001-01-01

    The results of the LEP experiments for rare B decays will be reviewed, covering hadronic final states, radiative and other rare decays and results for the inclusive charmless branching ratio. (8 refs).

  17. Quark-diagram analysis of charmed-baryon decays

    International Nuclear Information System (INIS)

    Kohara, Y.

    1991-01-01

    The Cabibbo-allowed two-body nonleptonic decays of charmed baryons to a SU(3)-octet (or -decuplet) baryon and a pseudoscalar meson are examined on the basis of the quark-diagram scheme. Some relations among the decay amplitudes or rates of various decay modes are derived. The decays of Ξ c + to a decuplet baryon are forbidden

  18. Higgs decays and brane gravi-vectors

    International Nuclear Information System (INIS)

    Clark, T. E.; Liu Boyang; Love, S. T.; Xiong, C.; Veldhuis, T. ter

    2008-01-01

    Higgs boson decays in flexible brane world models with stable, massive gravi-vectors are considered. Such vectors couple bilinearly to the standard model fields through either the standard model energy-momentum tensor, the weak hypercharge field strength, or the Higgs scalar. The role of the coupling involving the extrinsic curvature is highlighted. It is found that within the presently allowed parameter space, the decay rate of the Higgs into two gravi-vectors (which would appear as an invisible Higgs decay) can be comparable to the rate for any of the standard model decay modes.

  19. Probing the N = Z Line via β Decay

    International Nuclear Information System (INIS)

    Markku Oinonen

    1999-01-01

    This contribution reports several beta-decay studies performed at ISOLDE On-Line Mass Separator at CERN recently for nuclei close to N = Z line. Beta decay of 58 Zn provides a possibility to compare Gamow-Teller strength extracted from complementary beta-decay studies and charge-exchange reactions. Measurement on beta-decay half-life of 70 Kr shows importance of experimental information in modeling the path of the astrophysical rp process. Decay of 71 Kr is an example of a mirror beta decay and extends the systematics of these particular decays towards highly deformed region close to A = 80

  20. 103Pd decay

    International Nuclear Information System (INIS)

    Belyavenko, V.S.; Borozenets, G.P.; Vishnevskij, I.N.; Zheltonozhskij, V.A.

    1986-01-01

    103 Pd decay in different chemical states has been investigated. The change of the partial half-life period equal to 0.67±0.15% has been detected. The γ-spectrum has been measured to a high precision. The new data have been obtained on population probabilities of 103 Rh excited states and the total energy of decay for 103 Pd has been determined to a high precision (543.0±0.8). The values of log ft have been determined

  1. The decay width of stringy hadrons

    Science.gov (United States)

    Sonnenschein, Jacob; Weissman, Dorin

    2018-02-01

    In this paper we further develop a string model of hadrons by computing their strong decay widths and comparing them to experiment. The main decay mechanism is that of a string splitting into two strings. The corresponding total decay width behaves as Γ = π/2 ATL where T and L are the tension and length of the string and A is a dimensionless universal constant. We show that this result holds for a bosonic string not only in the critical dimension. The partial width of a given decay mode is given by Γi / Γ =Φi exp ⁡ (- 2 πCmsep2 / T) where Φi is a phase space factor, msep is the mass of the "quark" and "antiquark" created at the splitting point, and C is a dimensionless coefficient close to unity. Based on the spectra of hadrons we observe that their (modified) Regge trajectories are characterized by a negative intercept. This implies a repulsive Casimir force that gives the string a "zero point length". We fit the theoretical decay width to experimental data for mesons on the trajectories of ρ, ω, π, η, K*, ϕ, D, and Ds*, and of the baryons N, Δ, Λ, and Σ. We examine both the linearity in L and the exponential suppression factor. The linearity was found to agree with the data well for mesons but less for baryons. The extracted coefficient for mesons A = 0.095 ± 0.015 is indeed quite universal. The exponential suppression was applied to both strong and radiative decays. We discuss the relation with string fragmentation and jet formation. We extract the quark-diquark structure of baryons from their decays. A stringy mechanism for Zweig suppressed decays of quarkonia is proposed and is shown to reproduce the decay width of ϒ states. The dependence of the width on spin and flavor symmetry is discussed. We further apply this model to the decays of glueballs and exotic hadrons.

  2. Decay of superdeformed bands

    International Nuclear Information System (INIS)

    Carpenter, M.P.; Khoo, T.L.; Lauritsen, T.

    1995-01-01

    One of the major challenges in the study of superdeformation is to directly connect the large number of superdeformed bands now known to the yrast states. In this way, excitation energies, spins and parities can be assigned to the levels in the second well which is essential to establish the collective and single-particle components of these bands. This paper will review some of the progress which has been made to understand the decay of superdeformed bands using the new arrays including the measurement of the total decay spectrum and the establishment of direct one-step decays from the superdeformed band to the yrast line in 194 Hg. 42 refs., 5 figs

  3. Rare B-decays in the standard model

    International Nuclear Information System (INIS)

    Ali, A.; Greub, C.; Mannel, T.

    1993-02-01

    We review theoretical work done in studies of the Flavour Changing Neutral Current (FCNC) B-decays in the context of the Standard Model. Making use of the QCD-improved effective Hamiltonian describing the so-called vertical stroke ΔBvertical stroke =1 and vertical stroke ΔBvertical stroke =2, vertical stroke ΔQvertical stroke =0 transitions, we calculate the rates and differential distributions in a large number of B-decays. The FCNC processes discussed here include the radiative decays B → X s + γ, B → X d + γ, and the semileptonic decays B → X s l + l - , B → X d l + l - , B → X s ν l anti ν l , and B → X d ν l anti ν l . We also discuss the inclusive photon energy spectrum calculated from the Charged Current (CC) decays B → X c + γ and B → X u + γ and the mentioned FCNC radiative decays. The importance of carrying out measurements of the inclusive photon energy spectrum in B-decays is emphasized. Using phenomenological potential models and the Heavy Quark Effective Theory (HQET) we estimate decay branching ratios in a number of exclusive FCNC B-decays. Purely leptonic and photonic decays (B d , B s ) → l + l - and (B d , B s ) → γγ are also estimated. The principal interest in the studies of FCNC B-decays lies in their use in determining the parameters of the standard Model, in particular the CKM matrix elements and the top quark mass. The parametric dependence of these and other QCD-specific parameters on the rates and distributions is worked out numerically. (orig.)

  4. Search for Invisibly Decaying Higgs Bosons with Large Decay Width Using the OPAL Detector at LEP

    CERN Document Server

    Abbiendi, G.; Akesson, P.F.; Alexander, G.; Anagnostu, G.; Anderson, K.J.; Asai, S.; Axen, D.; Bailey, I.; Barberio, E.; Bailari, T.; Barlow, R.J.; Batly, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brown, Robert M.; Burckhart, H.J.; Campana, S.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Ciocca, C.; Csilling, A.; Cuffiani, M.; Dado, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Gagnon, P.; Gary, John William; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harel, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Herten, G.; Heuer, R.D.; Hill, J.C.; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kramer, T.; Krasznahorkay, A., Jr.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lellouch, D.; Letts, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, A.; Ludwig, J.; Mader, W.; Marcellini, S.; Martin, A.J.; Mashimo, T.; Mattig, Peter; McKenna, J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Meyer, N.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pilcher, J.E.; Pinfold, J.; Plane, D.E.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabertz, K.; Rembser, C.; Renkel, P.; Roney, J.M.; Rossi, A.M.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schorner-Sadenius, T.; Schroder, M.; Schumacher, M.; Seuster, R.; Shears, T.G.; shen, B.C.; sherwood, P.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Stahl, A.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija

    2007-01-01

    This paper describes a topological search for an invisibly decaying Higgs boson,H, produced via the Bjorken process (e+e- -> HZ). The analysis is based on data recorded using the OPAL detector at LEP at centre-of-mass energies from 183 to 209 GeV corresponding to a total integrated luminosity of 629pb-1. In the analysis only hadronic decays of the Z boson are considered. A scan over Higgs boson masses from 1 to 120 GeV and decay widths from 1 to 3000 GeV revealed no indication for a signal in the data. From a likelihood ratio of expected signal and Standard Model background we determine upper limits on cross-section times branching ratio to an invisible final state. For moderate Higgs boson decay widths, these range from about 0.07pb Mh = 60GeV) to 0.57pb (Mh = 114GeV). For decay widths above 200GeV the upper limits are of the order of 0.15pb. The results can be interpreted in general scenarios predicting a large invisible decay width of the Higgs boson. As an example we interpret the results in the so-called...

  5. Double beta decay: A theoretical overview

    International Nuclear Information System (INIS)

    Rosen, S.P.

    1988-01-01

    This paper reviews the theoretical possibility of double beta decay. The titles of the main sections of this paper are: Nuclear physics setting; Particle physics requirements; Kinematical features of the decay modes; Nuclear matrix elements; the Shell model and two-neutrino decay; Quasi-particle random phase approximation; and Future considerations. 18 refs., 7 tabs

  6. Contribution of short-lived nuclides to decay heat

    International Nuclear Information System (INIS)

    Katakura, Jun-ichi

    1987-01-01

    Comments are made on the calculation of decay heat, centering on evaluation of average decay energy. It is difficult to obtain sufficiently useful decay diagrams of short lived nucleides. High-energy levels are often missing in inferior decay diagrams, leading to an overestimation of the intensity of beta-rays at low-energy levels. Such an overestimation or underestimation due to the inferiority of a decay diagram is referred to as pandemonium effect. The pandemonium effect can be assessed by means of the ratio of the measured energy of the highest level of the daughter nuclide to the Q β -value of the beta-decay. When a satisfactory decay diagram cannot be obtained, the average decay energy has to be estimated by theoretical calculation. The gross theory for beta-decay proposed by Yamada and Takahashi is employed for the calculation. To carry out the calculation according to this theory, it is required to determine the value for the parameter Q 00 , the lowest energy of the daughter nuclide that meets the selection rule for beta-decay. Currently, Q 00 to be used for this purpose is estimated from data on the energy of the lowest level found in a decay diagram, even if it is inferior. Some examples of calculation of decay heat using the average beta- or gamma-ray energy are shown and compared with measurements. (author)

  7. Higher-order predictions for supersymmetric particle decays

    Energy Technology Data Exchange (ETDEWEB)

    Landwehr, Ananda Demian Patrick

    2012-06-12

    We analyze particle decays including radiative corrections at the next-to-leading order (NLO) within the Minimal Supersymmetric Standard Model (MSSM). If the MSSM is realized at the TeV scale, squark and gluino production and decays yield relevant rates at the LHC. Hence, in the first part of this thesis, we compute decay widths including QCD and electroweak NLO corrections to squark and gluino decays. Furthermore, the Higgs sector of the MSSM is enhanced compared to the one of the Standard Model. Thus, the additional Higgs bosons decay also into supersymmetric particles. These decays and the according NLO corrections are analyzed in the second part of this thesis. The calculations are performed within a common renormalization framework and numerically evaluated in specific benchmark scenarios.

  8. Nuclear structure and double beta decay

    International Nuclear Information System (INIS)

    Vogel, P.

    1988-01-01

    Double beta decay is a rare transition between two nuclei of the same mass number A involving a change of the nuclear charge Z by two units. It has long been recognized that the Oν mode of double beta decay, where two electrons and no neutrinos are emitted, is a powerful tool for the study of neutrino properties. Its observation would constitute a convincing proof that there exists a massive Majorana neutrino which couples to electrons. Double beta decay is a process involving an intricate mixture of particle physics and physics of the nucleus. The principal nuclear physics issues have to do with the evaluation of the nuclear matrix elements responsible for the decay. If the authors wish to arrive at quantitative answers for the neutrino properties the authors have no choice but to learn first how to understand the nuclear mechanisms. The authors describe first the calculation of the decay rate of the 2ν mode of double beta decay, in which two electrons and two antineutrinos are emitted

  9. PyDecay/GraphPhys: A Unified Language and Storage System for Particle Decay Process Descriptions

    Energy Technology Data Exchange (ETDEWEB)

    Dunietz, Jesse N.; /MIT /SLAC

    2011-06-22

    To ease the tasks of Monte Carlo (MC) simulation and event reconstruction (i.e. inferring particle-decay events from experimental data) for long-term BaBar data preservation and analysis, the following software components have been designed: a language ('GraphPhys') for specifying decay processes, common to both simulation and data analysis, allowing arbitrary parameters on particles, decays, and entire processes; an automated visualization tool to show graphically what decays have been specified; and a searchable database storage mechanism for decay specifications. Unlike HepML, a proposed XML standard for HEP metadata, the specification language is designed not for data interchange between computer systems, but rather for direct manipulation by human beings as well as computers. The components are interoperable: the information parsed from files in the specification language can easily be rendered as an image by the visualization package, and conversion between decay representations was implemented. Several proof-of-concept command-line tools were built based on this framework. Applications include building easier and more efficient interfaces to existing analysis tools for current projects (e.g. BaBar/BESII), providing a framework for analyses in future experimental settings (e.g. LHC/SuperB), and outreach programs that involve giving students access to BaBar data and analysis tools to give them a hands-on feel for scientific analysis.

  10. Status of decay data of fission products

    International Nuclear Information System (INIS)

    Blachot, J.

    1978-01-01

    Fission products (F.P.) are neutron rich isotopes ranging from Zn to Tm. The status of decay data of F.P. was described at the Bologna Panel 1973 by Rudstam. Since then, FPND have improved in general, but still much is valid of what Rudstam said about the accuracies of FPND. The lack of decay data for the short lived F.P. has been considerably reduced, and some of the short lived F.P. have now well studied decay data. The present status of decay data is given in this review, which is composed of six sections. In the first one, the principal new facilities used in decay data measurements are reviewed. The second part is devoted to the total decay energy (Q). In the third Section, the half lives are treated. In the fourth and fifth Sections, beta and gamma energies and intensities, and also average values are discussed. Finally, the last Section considers the different files and compilations devoted to the decay of F.P

  11. Decay properties of heavier nuclei and mass formula

    International Nuclear Information System (INIS)

    Uno, Masahiro

    2000-01-01

    The stabilities of heavy nuclei, including super-heavy elements, are governed by alpha decay and fission. Some exotic types of decay, such as heavy cluster decay, which does not occur so frequently as to govern stability, have been also reported. The half-time estimations of various types of decay are reviewed. And the possibility of decay, mainly in case of heavy cluster decay, is discussed with Q-value obtained from mass formulae as well. Some topics concerning other types of exotic decay are presented. Recent trends in the research on mass formula are reviewed from the historical point of view, to get perspectives of future development. (Yamamoto, A.)

  12. Decay properties of heavier nuclei and mass formula

    Energy Technology Data Exchange (ETDEWEB)

    Uno, Masahiro [Ministry of Education, Science and Culture, Tokyo (Japan)

    2000-03-01

    The stabilities of heavy nuclei, including super-heavy elements, are governed by alpha decay and fission. Some exotic types of decay, such as heavy cluster decay, which does not occur so frequently as to govern stability, have been also reported. The half-time estimations of various types of decay are reviewed. And the possibility of decay, mainly in case of heavy cluster decay, is discussed with Q-value obtained from mass formulae as well. Some topics concerning other types of exotic decay are presented. Recent trends in the research on mass formula are reviewed from the historical point of view, to get perspectives of future development. (Yamamoto, A.)

  13. Number of detectable kaon decays at LAMPF II

    International Nuclear Information System (INIS)

    Sanford, T.W.L.

    1982-04-01

    The maximum number of kaon decays detectable at LAMPF II is estimated for both in-flight and stopping decays. Under reasonable assumptions, the momentum of the kaon beam that optimizes the decay yield occurs at about 6 GeV/c and 600 MeV/c for in-flight and stopping decays, respectively. K + decay yields are fo the order of 7 x 10 7 per 10 14 interacting with K - yields being typically 5 times less. By measuring decays from such beams, a statistical limit of 10 -15 on a branching ratio to a particular channel can be placed in a 100-day run. The large number of kaon decays available at LAMPF II thus provides a powerful tool for sensitively examining rare-decay processes of the kaon

  14. QCD in heavy quark production and decay

    Energy Technology Data Exchange (ETDEWEB)

    Wiss, J. [Univ. of Illinois, Urbana, IL (United States)

    1997-06-01

    The author discusses how QCD is used to understand the physics of heavy quark production and decay dynamics. His discussion of production dynamics primarily concentrates on charm photoproduction data which are compared to perturbative QCD calculations which incorporate fragmentation effects. He begins his discussion of heavy quark decay by reviewing data on charm and beauty lifetimes. Present data on fully leptonic and semileptonic charm decay are then reviewed. Measurements of the hadronic weak current form factors are compared to the nonperturbative QCD-based predictions of Lattice Gauge Theories. He next discusses polarization phenomena present in charmed baryon decay. Heavy Quark Effective Theory predicts that the daughter baryon will recoil from the charmed parent with nearly 100% left-handed polarization, which is in excellent agreement with present data. He concludes by discussing nonleptonic charm decay which is traditionally analyzed in a factorization framework applicable to two-body and quasi-two-body nonleptonic decays. This discussion emphasizes the important role of final state interactions in influencing both the observed decay width of various two-body final states as well as modifying the interference between interfering resonance channels which contribute to specific multibody decays. 50 refs., 77 figs.

  15. QCD in heavy quark production and decay

    International Nuclear Information System (INIS)

    Wiss, J.

    1997-01-01

    The author discusses how QCD is used to understand the physics of heavy quark production and decay dynamics. His discussion of production dynamics primarily concentrates on charm photoproduction data which are compared to perturbative QCD calculations which incorporate fragmentation effects. He begins his discussion of heavy quark decay by reviewing data on charm and beauty lifetimes. Present data on fully leptonic and semileptonic charm decay are then reviewed. Measurements of the hadronic weak current form factors are compared to the nonperturbative QCD-based predictions of Lattice Gauge Theories. He next discusses polarization phenomena present in charmed baryon decay. Heavy Quark Effective Theory predicts that the daughter baryon will recoil from the charmed parent with nearly 100% left-handed polarization, which is in excellent agreement with present data. He concludes by discussing nonleptonic charm decay which is traditionally analyzed in a factorization framework applicable to two-body and quasi-two-body nonleptonic decays. This discussion emphasizes the important role of final state interactions in influencing both the observed decay width of various two-body final states as well as modifying the interference between interfering resonance channels which contribute to specific multibody decays. 50 refs., 77 figs

  16. Dispersion Decay and Scattering Theory

    CERN Document Server

    Komech, Alexander

    2012-01-01

    A simplified, yet rigorous treatment of scattering theory methods and their applications Dispersion Decay and Scattering Theory provides thorough, easy-to-understand guidance on the application of scattering theory methods to modern problems in mathematics, quantum physics, and mathematical physics. Introducing spectral methods with applications to dispersion time-decay and scattering theory, this book presents, for the first time, the Agmon-Jensen-Kato spectral theory for the Schr?dinger equation, extending the theory to the Klein-Gordon equation. The dispersion decay plays a crucial role i

  17. Flavor mixing and charm decay

    International Nuclear Information System (INIS)

    Chau Wang, L.C.

    1980-01-01

    The results of mixing matrix determination and their implications on heavy quark decays are given. The decays of charm mesons D 0 , D + , F + into two pseudoscalar mesons are discussed in the framework of SU(3) symmetry. The charm decays are also discussed in terms of quark diagrams. It is demonstrated that the differences observed in the lifetimes of D 0 and D + , and in the branching ratios B(D 0 → K - K + ) and B(D 0 → π - π + ) can be easily incorporated. 3 figures

  18. Do protons decay

    International Nuclear Information System (INIS)

    Litchfield, P.J.

    1984-09-01

    The experimental status of proton decay is reviewed after the Leipzig International conference, July 1984. A brief comparative description of the currently active experiments is given. From the overall samples of contained events it can be concluded that the experiments are working well and broadly agree with each other. The candidates for proton decay from each experiment are examined. Although several experiments report candidates at a higher rate than expected from background calculations, the validity of these calculations is still open to doubt. (author)

  19. Majorana neutrinos and double beta-decay

    International Nuclear Information System (INIS)

    Shchepkin, M.G.

    1986-01-01

    Problem, related to neutrino mass and lepton charge L conservation is briefly discussed. A possibility to experimentally test L conservation in different processes and to produce limitations for neutrino mass in double beta-decay processes is considered. Planned experiments on studying the double neutrinoless (2β) beta-decays and searching 2β(2ν)-decays, permitted by the conservation laws, are discussed. It is stressed, that comparison of the existing theoretical predictions of 2β(2ν)-decay probability with experimental results will make it possible to choose the most adequate approach to the calculation of double β-transition nuclear amplitudes

  20. Strong effects in weak nonleptonic decays

    International Nuclear Information System (INIS)

    Wise, M.B.

    1980-04-01

    In this report the weak nonleptonic decays of kaons and hyperons are examined with the hope of gaining insight into a recently proposed mechanism for the ΔI = 1/2 rule. The effective Hamiltonian for ΔS = 1 weak nonleptonic decays and that for K 0 -anti K 0 mixing are calculated in the six-quark model using the leading logarithmic approximation. These are used to examine the CP violation parameters of the kaon system. It is found that if Penguin-type diagrams make important contributions to K → ππ decay amplitudes then upcoming experiments may be able to distinguish the six-quark model for CP violation from the superweak model. The weak radiative decays of hyperons are discussed with an emphasis on what they can teach us about hyperon nonleptonic decays and the ΔI = 1/2 rule

  1. Leptonic decays of the $D_s$ meson

    CERN Document Server

    Heister, A.; Barate, R.; De Bonis, I.; Decamp, D.; Goy, C.; Lees, J.P.; Merle, E.; Minard, M.N.; Pietrzyk, B.; Boix, G.; Bravo, S.; Casado, M.P.; Chmeissani, M.; Crespo, J.M.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, L.; Grauges, E.; Martinez, M.; Merino, G.; Miquel, R.; Mir, L.M.; Pacheco, A.; Ruiz, H.; Colaleo, A.; Creanza, D.; de Palma, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Tricomi, A.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Abbaneo, D.; Azzurri, P.; Buchmuller, O.; Cattaneo, M.; Cerutti, F.; Clerbaux, B.; Drevermann, H.; Forty, R.W.; Frank, M.; Gianotti, F.; Greening, T.C.; Hansen, J.B.; Harvey, J.; Hutchcroft, D.E.; Janot, P.; Jost, B.; Kado, M.; Mato, P.; Moutoussi, A.; Ranjard, F.; Rolandi, Gigi; Schlatter, D.; Schneider, O.; Sguazzoni, G.; Tejessy, W.; Teubert, F.; Valassi, A.; Videau, I.; Ward, J.; Badaud, F.; Falvard, A.; Gay, P.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.C.; Pallin, D.; Perret, P.; Hansen, J.D.; Hansen, J.R.; Hansen, P.H.; Nilsson, B.S.; Waananen, A.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Bonneaud, G.; Brient, J.C.; Rouge, A.; Rumpf, M.; Swynghedauw, M.; Verderi, M.; Videau, H.; Ciulli, V.; Focardi, E.; Parrini, G.; Antonelli, A.; Antonelli, M.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Chiarella, V.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G.P.; Passalacqua, L.; Pepe-Altarelli, M.; Spagnolo, P.; Halley, A.; Lynch, J.G.; Negus, P.; O'Shea, V.; Raine, C.; Thompson, A.S.; Wasserbaech, S.; Cavanaugh, R.; Dhamotharan, S.; Geweniger, C.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E.E.; Putzer, A.; Sommer, J.; Stenzel, H.; Tittel, K.; Werner, S.; Wunsch, M.; Beuselinck, R.; Binnie, D.M.; Cameron, W.; Dornan, P.J.; Girone, M.; Marinelli, N.; Sedgbeer, J.K.; Thompson, J.C.; Ghete, V.M.; Girtler, P.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bouhova-Thacker, E.; Bowdery, C.K.; Finch, A.J.; Foster, F.; Hughes, G.; Jones, R.W.L.; Pearson, M.R.; Robertson, N.A.; Jakobs, K.; Kleinknecht, K.; Quast, G.; Renk, B.; Sander, H.G.; Wachsmuth, H.; Zeitnitz, C.; Bonissent, A.; Carr, J.; Coyle, P.; Leroy, O.; Payre, P.; Rousseau, D.; Talby, M.; Ragusa, F.; David, A.; Dietl, H.; Ganis, G.; Huttmann, K.; Lutjens, G.; Mannert, C.; Manner, W.; Moser, H.G.; Settles, R.; Wiedenmann, W.; Wolf, G.; Boucrot, J.; Callot, O.; Davier, M.; Duflot, L.; Grivaz, J.F.; Heusse, P.; Jacholkowska, A.; Lefrancois, J.; Veillet, J.J.; Yuan, C.; Bagliesi, Giuseppe; Boccali, T.; Foa, L.; Giammanco, A.; Giassi, A.; Ligabue, F.; Messineo, A.; Palla, F.; Sanguinetti, G.; Sciaba, A.; Tenchini, R.; Venturi, A.; Verdini, P.G.; Blair, G.A.; Cowan, G.; Green, M.G.; Medcalf, T.; Misiejuk, A.; Strong, J.A.; Teixeira-Dias, P.; von Wimmersperg-Toeller, J.H.; Clifft, R.W.; Edgecock, T.R.; Norton, P.R.; Tomalin, I.R.; Bloch-Devaux, Brigitte; Colas, P.; Emery, S.; Kozanecki, W.; Lancon, E.; Lemaire, M.C.; Locci, E.; Perez, P.; Rander, J.; Renardy, J.F.; Roussarie, A.; Schuller, J.P.; Schwindling, J.; Trabelsi, A.; Vallage, B.; Konstantinidis, N.; Litke, A.M.; Taylor, G.; Booth, C.N.; Cartwright, S.; Combley, F.; Lehto, M.; Thompson, L.F.; Affholderbach, K.; Boehrer, Armin; Brandt, S.; Grupen, C.; Ngac, A.; Prange, G.; Sieler, U.; Giannini, G.; He, H.; Putz, J.; Rothberg, J.; Armstrong, S.R.; Berkelman, Karl; Cranmer, K.; Ferguson, D.P.S.; Gao, Y.; Gonzalez, S.; Hayes, O.J.; Hu, H.; Jin, S.; Kile, J.; McNamara, P.A., III; Nielsen, J.; Pan, Y.B.; von Wimmersperg-Toeller, J.H.; Wiedenmann, W.; Wu, J.; Wu, Sau Lan; Wu, X.; Zobernig, G.; Dissertori, G.

    2002-01-01

    The purely leptonic decays Ds -> tau nu and Ds -> mu nu are studied in a sample of four million hadronic Z decays collected with the ALEPH detector at the LEP e+e- collider from 1991 to 1995. The branching fractions are extracted from a combination of two analyses, one optimized to select Ds -> tau nu decays with tau -> e nu nubar or mu nu nubar, and the other optimized for Ds-> mu nu decays. The results are used to evaluate the Ds decay constant, within the Standard Model: fDs = [285 +- 19(stat) +- 40 (syst)] MeV.

  2. Multiple preequilibrium decay processes

    International Nuclear Information System (INIS)

    Blann, M.

    1987-11-01

    Several treatments of multiple preequilibrium decay are reviewed with emphasis on the exciton and hybrid models. We show the expected behavior of this decay mode as a function of incident nucleon energy. The algorithms used in the hybrid model treatment are reviewed, and comparisons are made between predictions of the hybrid model and a broad range of experimental results. 24 refs., 20 figs

  3. Family symmetries and proton decay

    International Nuclear Information System (INIS)

    Murayama, Hitoshi; Kaplan, D.B.

    1994-01-01

    The proton decay modes p → K 0 e + and p → K 0 μ + may be visible in certain supersymmetric theories, and if seen would provide evidence for new flavor physics at extremely short distances. These decay modes can arise from the dimension five operator (Q 1 Q 1 Q 2 L 1,2 ), where Q i and L i are i th generation quark and lepton superfields respectively. Such an operator is not generated at observable levels due to gauge or Higgs boson exchange in a minimal GUT. However in theories that explain the fermion mass hierarchy, it may be generated at the Planck scale with a strength such that the decays p → K 0 ell + are both compatible with the proton lifetime and visible at Super-Kamiokande. Observable proton decay can even occur in theories without unification

  4. Inflaton decay through supergravity effects

    International Nuclear Information System (INIS)

    Endo, M.; Takahashi, F.; Kawasaki, M.; Yanagida, T.T.; Tokyo Univ.

    2006-07-01

    We point out that supergravity effects enable the inflaton to decay into all matter fields, including the visible and the supersymmetry breaking sectors, once the inflaton acquires a non-vanishing vacuum expectation value. The new decay processes have great impacts on cosmology; the reheating temperature is bounded below; the gravitinos are produced by the inflaton decay in a broad class of the dynamical supersymmetry breaking models. We derive the bounds on the inflaton mass and the vacuum expectation value, which severely constrain high-scale inflations such as the hybrid and chaotic inflation models. (orig.)

  5. Decay of heavy and superheavy nuclei

    Indian Academy of Sciences (India)

    April 2014 physics pp. 705–715. Decay of heavy and superheavy nuclei ... study on the feasibility of observing α decay chains from the isotopes of the ... studies on 284−286115 and 288−292117 will be a guide to future experiments. .... ratio of the α decay from the ground state of the parent nucleus to the level i of the.

  6. The statistical decay of very hot nuclei: from sequential decay to multifragmentation

    International Nuclear Information System (INIS)

    Carlson, B.V.; Donangelo, R.; Universidad de la Republica, Montevideo; Souza, S.R.; Universidade Federal do Rio Grande do Sul; Lynch, W.G.; Steiner, A.W.; Tsang, M.B.

    2010-01-01

    Full text. At low excitation energies, the compound nucleus typically decays through the sequential emission of light particles. As the energy increases, the emission probability of heavier fragments increases until, at sufficiently high energies, several heavy complex fragments are emitted during the decay. The extent to which this fragment emission is simultaneous or sequential has been a subject of theoretical and experimental study for almost 30 years. The Statistical Multifragmentation Model, an equilibrium model of simultaneous fragment emission, uses the configurations of a statistical ensemble to determine the distribution of primary fragments of a compound nucleus. The primary fragments are then assumed to decay by sequential compound emission or Fermi breakup. As the first step toward a more unified model of these processes, we demonstrate the equivalence of a generalized Fermi breakup model, in which densities of excited states are taken into account, to the microcanonical version of the statistical multifragmentation model. We then establish a link between this unified Fermi breakup / statistical multifragmentation model and the well-known process of compound nucleus emission, which permits to consider simultaneous and sequential emission on the same footing. Within this unified framework, we analyze the increasing importance of simultaneous, multifragment decay with increasing excitation energy and decreasing lifetime of the compound nucleus. (author)

  7. Search for spontaneous fission of 226Ra and systematics of the spontaneous fission, α-decay and cluster decay probabilities

    International Nuclear Information System (INIS)

    Mikheev, V.L.; Tret'yakova, S.P.; Golovchenko, A.N.; Timofeeva, O.V.; Hussonnois, M.; Le Naour, C.

    1998-01-01

    The low limit of the 226 Ra spontaneous fission half-life corresponding to T 1/2 ≥ 4 · 10 18 years is measured. The 226 Ra spontaneous fission probability proved to be about 50 times less than the value expected from the known systematics, connecting the ratios of theα-decay and spontaneous fission probabilities with the fissility parameter Z 2 /A. It is shown that the probabilities of spontaneous fission, α-decay and cluster decay can be systematized in the same way according to the difference between the decay products Coulomb energy near the scission point and decay energy Q

  8. Experimental status of B decays

    International Nuclear Information System (INIS)

    Horwitz, N.

    1987-01-01

    This paper reviews the status of a number of current B-meson decay topics. Topics reviewed are: B reconstruction, penguins and rare decay modes, is there a charm deficit?, V ub /V bc , new limit on FCNC. Results are presented

  9. Cosmology with decaying particles

    International Nuclear Information System (INIS)

    Turner, M.S.

    1984-09-01

    We consider a cosmological model in which an unstable massive relic particle species (denoted by X) has an initial mass density relative to baryons β -1 identically equal rho/sub X//rho/sub B/ >> 1, and then decays recently (redshift z less than or equal to 1000) into particles which are still relativistic today (denoted by R). We write down and solve the coupled equations for the cosmic scale factor a(t), the energy density in the various components (rho/sub X/, rho/sub R/, rho/sub B/), and the growth of linear density perturbations (delta rho/rho). The solutions form a one parameter (β) family of solutions; physically β -1 approx. = (Ω/sub R//Ω/sub NR/) x (1 + z/sub D/) = (ratio today of energy density of relativistic to nonrelativistic particles) x (1 + redshift of (decay)). We discuss the observational implications of such a cosmological model and compare our results to earlier results computed in the simultaneous decay approximation. In an appendix we briefly consider the case where one of the decay products of the X is massive and becomes nonrelativistic by the present epoch. 21 references

  10. Cosmology with decaying particles

    Energy Technology Data Exchange (ETDEWEB)

    Turner, M.S.

    1984-09-01

    We consider a cosmological model in which an unstable massive relic particle species (denoted by X) has an initial mass density relative to baryons ..beta../sup -1/ identically equal rho/sub X//rho/sub B/ >> 1, and then decays recently (redshift z less than or equal to 1000) into particles which are still relativistic today (denoted by R). We write down and solve the coupled equations for the cosmic scale factor a(t), the energy density in the various components (rho/sub X/, rho/sub R/, rho/sub B/), and the growth of linear density perturbations (delta rho/rho). The solutions form a one parameter (..beta..) family of solutions; physically ..beta../sup -1/ approx. = (..cap omega../sub R//..cap omega../sub NR/) x (1 + z/sub D/) = (ratio today of energy density of relativistic to nonrelativistic particles) x (1 + redshift of (decay)). We discuss the observational implications of such a cosmological model and compare our results to earlier results computed in the simultaneous decay approximation. In an appendix we briefly consider the case where one of the decay products of the X is massive and becomes nonrelativistic by the present epoch. 21 references.

  11. Observation of charmless hadronic B decays

    CERN Document Server

    Buskulic, Damir; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Nief, J Y; Odier, P; Pietrzyk, B; Casado, M P; Chmeissani, M; Crespo, J M; Delfino, M C; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Juste, A; Martínez, M; Orteu, S; Padilla, C; Park, I C; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Alemany, R; Bazarko, A O; Bonvicini, G; Bright-Thomas, P G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Lutters, G; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Moneta, L; Oest, T; Pacheco, A; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rizzo, G; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schmitt, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wagner, A; Ajaltouni, Ziad J; Barrès, A; Boyer, C; Falvard, A; Gay, P; Henrard, P; Jousset, J; Michel, B; Monteil, S; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rosnet, P; Rossignol, J M; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Rensch, B; Wäänänen, A; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Rougé, A; Rumpf, M; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Casper, David William; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Knowles, I G; Lynch, J G; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Teixeira-Dias, P; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Geweniger, C; Graefe, G; Hanke, P; Hansper, G; Hepp, V; Kluge, E E; Putzer, A; Schmidt, M; Sommer, J; Tittel, K; Werner, S; Wunsch, M; Abbaneo, D; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, Peter J; Moutoussi, A; Nash, J; Sedgbeer, J K; Stacey, A M; Williams, M D; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Betteridge, A P; Bowdery, C K; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Williams, M I; Galla, A; Giehl, I; Greene, A M; Jakobs, K; Kleinknecht, K; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Konstantinidis, N P; Payre, P; Rousseau, D; Talby, M; Sadouki, A; Thulasidas, M; Trabelsi, K; Aleppo, M; Ragusa, F; Bauer, C; Berlich, R; Blum, Walter; Büscher, V; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Stenzel, H; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Choi, Y; Cordier, A; Davier, M; Duflot, L; Grivaz, J F; Höcker, A; Jacholkowska, A; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Nikolic, I A; Park, H J; Schune, M H; Simion, S; Veillet, J J; Videau, I; Zerwas, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Palla, Fabrizio; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Vannini, C; Verdini, P G; Walsh, J; Blair, G A; Bryant, L M; Cerutti, F; Chambers, J T; Gao, Y; Green, M G; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Maley, P; Norton, P R; Thompson, J C; Wright, A E; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Black, S N; Dann, J H; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Booth, C N; Boswell, R; Brew, C A J; Cartwright, S L; Combley, F; Köksal, A; Lehto, M H; Newton, W M; Reeve, J; Thompson, L F; Böhrer, A; Brandt, S; Cowan, G D; Grupen, Claus; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Greening, T C; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Scott, I J; Walsh, A M; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

    1996-01-01

    Four candidates for charmless hadronic B decay are observed in a data sample of four million hadronic Z decays recorded by the {\\sc aleph} detector at {\\sc lep} . The probability that these events come from background sources is estimated to b e less than $10^{-6}$. The average branching ratio of weakly decaying B hadrons (a mixture of $\\bd$, $\\bs$ and $\\lb$ weighted by their production cross sections and lifetimes , here denoted B) into two long-lived charged hadrons (pions, kaons or protons) is measured to be $\\Br(\\btohh) = \\resultBR$. The relative branching fraction $\\rratio$, where $\\rs$ is the ratio of $\\bs$ to $\\bd$ decays in the sample, is measured to be $\\resultR$. %Branching ratio upper limits are also obtained for a variety In addition, branching ratio upper limits are obtained for a variety of exclusive charmless hadronic two-body decays of B hadrons.

  12. Non-Leptonic Weak Decays of B Mesons

    CERN Document Server

    Neubert, Matthias; Neubert, Matthias; Stech, Berthold

    1997-01-01

    We present a detailed study of non-leptonic two-body decays of B mesons based on a generalized factorization hypothesis. We discuss the structure of non-factorizable corrections and present arguments in favour of a simple phenomenological description of their effects. To evaluate the relevant transition form factors in the factorized decay amplitudes, we use information extracted from semileptonic decays and incorporate constraints imposed by heavy-quark symmetry. We discuss tests of the factorization hypothesis and show how unknown decay constants may be determined from non-leptonic decays. In particular, we find f_{Ds}=(234+-25) MeV and f_{Ds*}=(271+-33) MeV.

  13. Spectroscopy of element 115 decay chains

    Energy Technology Data Exchange (ETDEWEB)

    Rudolph, Dirk [Lund University, Sweden; Forsberg, U. [Lund University, Sweden; Golubev, P. [Lund University, Sweden; Sarmiento, L. G. [Lund University, Sweden; Yakushev, A. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Andersson, L.-L. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Di Nitto, A. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Duehllmann, Ch. E. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Gates, J. M. [Lawrence Berkeley National Laboratory (LBNL); Gregorich, K. E. [Lawrence Berkeley National Laboratory (LBNL); Gross, Carl J [ORNL; Hessberger, F. P. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Herzberg, R.-D [University of Liverpool; Khuyagbaatar, J. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Kratz, J. V. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Rykaczewski, Krzysztof Piotr [ORNL; Schaedel, M. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Aberg, S. [Lund University, Sweden; Ackermann, D. [GSI-Hemholtzzentrum fur Schwerionenforschung, Darmstadt, Germany; Block, M. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Brand, H. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Carlsson, B. G. [Lund University, Sweden; Cox, D. [University of Liverpool; Derkx, X. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Eberhardt, K. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Even, J. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Fahlander, C. [Lund University, Sweden; Gerl, J. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Jaeger, E. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kindler, B. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Krier, J. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kojouharov, I. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kurz, N. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Lommel, B. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Mistry, A. [University of Liverpool; Mokry, C. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Nitsche, H. [Lawrence Berkeley National Laboratory (LBNL); Omtvedt, J. P. [Paul Scherrer Institut, Villigen, Switzerland; Papadakis, P. [University of Liverpool; Ragnarsson, I. [Lund University, Sweden; Runke, J. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Schaffner, H. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Schausten, B. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Thoerle-Pospiech, P. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Torres, T. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Traut, T. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Trautmann, N. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Tuerler, A. [Paul Scherrer Institut, Villigen, Switzerland; Ward, A. [University of Liverpool; Ward, D. E. [Lund University, Sweden; Wiehl, N. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany

    2013-01-01

    A high-resolution a, X-ray and -ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum fu r Schwerionenforschung. Thirty correlated a-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z = 115. The data includes first candidates of fingerprinting the decay step Mt --> Bh with characteristic X rays. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z > 112. Comprehensive Monte-Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation.

  14. Bs mesons: semileptonic and nonleptonic decays

    Directory of Open Access Journals (Sweden)

    Albertus C.

    2014-01-01

    Full Text Available In this contribution we compute some nonleptonic and semileptonic decay widths of Bs mesons, working in the context of constituent quark models [1, 2]. For the case of semileptonic decays we consider reactions leading to kaons or different Jπ Ds mesons. The study of nonleptonic decays has been done in the factorisation approximation and includes the final states enclosed in Table 2.

  15. Tau decays: A theoretical perspective

    International Nuclear Information System (INIS)

    Marciano, W.J.

    1992-11-01

    Theoretical predictions for various tau decay rates are reviewed. Effects of electroweak radiative corrections are described. Implications for precision tests of the standard model and ''new physics'' searches are discussed. A perspective on the tau decay puzzle and 1-prong problem is given

  16. Weak radiative baryonic decays of B mesons

    International Nuclear Information System (INIS)

    Kohara, Yoji

    2004-01-01

    Weak radiative baryonic B decays B→B 1 B 2 -barγ are studied under the assumption of the short-distance b→sγ electromagnetic penguin transition dominance. The relations among the decay rates of various decay modes are derived

  17. Decay power evaluation for licensing analysis

    International Nuclear Information System (INIS)

    Tran, H.; Schrock, V.E.

    1987-01-01

    The ANSI/ANS 5.1-1979 Standard on Decay Power in shutdown reactors has been available as the basis for accident analysis for the past 7 yr. The US Nuclear Regulatory Commission has made a commitment to use this standard in new licensing approaches and has approved a licensing model for boiling water. More sweeping changes in the licensing rules are currently under review that will involve the use of best-estimate models and a statistical evaluation of the uncertainty (95% confidence level) in the key results. The structure of the decay power standard is well suited for such applications because it provides a statistically meaningful uncertainty in the decay power from fission products. The normalized decay power is a function specific to each point in the reactor volume due to the fact that the fuel composition develops a spatial dependence as burnup proceeds and decay power depends on the mix of fissioning nuclides. For reactor safety calculations it is desirable to employ a single temporal decay power function for the whole core inasmuch as many variations of accident parameters are required. This is the usual approach in large system thermal-hydraulics codes. Such a single representative or generic curve for a specified total operating power history can be acceptable but at the expense of some increase in the uncertainty. In this paper, the author present a method of evaluating the additional uncertainty in the decay power associated with use of a generic curve

  18. Search for charmless decays of B hadrons in hadronic and radiative (b --> s gamma) decay modes using the DELPHI detector

    CERN Document Server

    Liko, Dietrich

    1995-01-01

    Charmless decays of B hadrons have been of considerable interest during the last years. Decays in hadronic modes proceed either trough tree level b � u transitions or loop diagrams involving so-called "hadronic" penguins. Tree level dominated decays confirm the non zero value of JVubl in the CKM mixing matrix while those induced by penguin processes provide tests of the loop structure of the Standard Model. Decays in the radiative modes b -+ s-y are forbidden at tree level and proceed only trough loop diagrams. Possible contributions to the decay rate due to new physics provide a test of the Standard Model. During the last years various measurements of decay rates have been performed at colliders at the bb-threshold. Experiments at the LEP collider have already collected sufficient data to study these decays in a different experimental environment. Results of searches at the DELPHI experiment are presented.

  19. Radioactive decay data tables: a handbook of decay data for application to radiation dosimetry and radiological assessments

    International Nuclear Information System (INIS)

    Kocher, D.C.

    1982-01-01

    Reviews compendium containing recommended decay data for approx. 500 radionuclides of interest in nuclear medicine and fusion reactor technology or of potential importance in routine or accidental releases from the nuclear fuel cycle. Primary source of the decay data presented in this handbook is the Evaluated Nuclear Structure Data File (ENSDF), developed and maintained by the US Nuclear Data Network. Topics covered include various radioactive decay processes; evaluation process and standards of ENSDF; tables and computer code MEDLIST used to produce ENSDF tables; radiation dosimetry and radiological assessments; parent-daughter activity ratios wherever the adopted decay data may contain significant uncertainties or errors due to the lack of appropriate experimental data

  20. Decay of the Bottom mesons

    International Nuclear Information System (INIS)

    Duong Van Phi; Duong Anh Duc

    1992-12-01

    The channels of the decay of Bottom mesons are deduced from a selection rule and the Lagrangians which are formed on the LxO(4) invariance and the principle of minimal structure. The estimation of the corresponding decay probabilities are considered. (author). 21 refs

  1. Charm counting in b decays

    CERN Document Server

    Buskulic, Damir; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Nief, J Y; Odier, P; Pietrzyk, B; Casado, M P; Chmeissani, M; Crespo, J M; Delfino, M C; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Carrido, L; Juste, A; Martínez, M; Orteu, S; Padilla, C; Park, I C; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Tricomi, A; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Alemany, R; Bazarko, A O; Bonvicini, G; Bright-Thomas, P G; Cattaneo, M; Cerutti, F; Comas, P; Coyle, P; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Lutters, G; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Mir, L M; Moneta, L; Oest, T; Pacheco, A; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rizzo, G; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schmitt, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wagner, A; Ajaltouni, Ziad J; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rosnet, P; Rossignol, J M; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Rensch, B; Wäänänen, A; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Rougé, A; Rumpf, M; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Casper, David William; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Knowles, I G; Lynch, J G; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Teixeira-Dias, P; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Geweniger, C; Graefe, G; Hanke, P; Hansper, G; Hepp, V; Kluge, E E; Putzer, A; Schmidt, M; Sommer, J; Tittel, K; Werner, S; Wunsch, M; Abbaneo, D; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, Peter J; Moutoussi, A; Nash, J; Sedgbeer, J K; Stacey, A M; Williams, M D; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Betteridge, A P; Bowdery, C K; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Williams, M I; Galla, A; Giehl, I; Greene, A M; Hoffmann, C; Jakobs, K; Kleinknecht, K; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Konstantinidis, N P; Payre, P; Rousseau, D; Talby, M; Sadouki, A; Thulasidas, M; Trabelsi, K; Aleppo, M; Ragusa, F; Bauer, C; Berlich, R; Blum, Walter; Büscher, V; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Stenzel, H; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Choi, Y; Cordier, A; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Höcker, A; Jacholkowska, A; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Nikolic, I A; Park, H J; Schune, M H; Simion, S; Veillet, J J; Videau, I; Zerwas, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Palla, Fabrizio; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Vannini, C; Verdini, P G; Blair, G A; Bryant, L M; Chambers, J T; Gao, Y; Green, M G; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Maley, P; Norton, P R; Thompson, J C; Wright, A E; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Black, S N; Dann, J H; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Booth, C N; Boswell, R; Brew, C A J; Cartwright, S L; Combley, F; Köksal, A; Lehto, M H; Newton, W M; Reeve, J; Thompson, L F; Böhrer, A; Brandt, S; Cowan, G D; Grupen, Claus; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Greening, T C; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Scott, I J; Walsh, A M; Walsh, J; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

    1996-01-01

    The inclusive production of charmed particles in Z -> bb decays has been measured from the yield of D^0, D^+, D^+_s and Lambda_{c}^+ decays in a sample of qq events with high b purity collected with the ALEPH detector from 1992 to 1995. From these measurements, adding the charmonia production rate and an estimate of the charmed strange baryon contribution, the average number of charm quarks per b decay is determined to be n_c = 1.230 \\pm 0.036 \\pm 0.038 \\pm 0.053 where the uncertainties are due to statistics, systematic effects and branching ratios, respectively.

  2. Charm counting in b decays

    Science.gov (United States)

    Buskulic, D.; de Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J.-P.; Lucotte, A.; Minard, M.-N.; Nief, J.-Y.; Odier, P.; Pietrzyk, B.; Casado, M. P.; Chmeissani, M.; Crespo, J. M.; Delfino, M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, Ll.; Juste, A.; Martinez, M.; Orteu, S.; Padilla, C.; Park, I. C.; Pascual, A.; Perlas, J. A.; Riu, I.; Sanchez, F.; Teubert, F.; Colaleo, A.; Creanza, D.; de Palma, M.; Gelao, G.; Girone, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Marinelli, N.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Tricomi, A.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Alemany, R.; Bazarko, A. O.; Bonvicini, G.; Bright-Thomas, P.; Cattaneo, M.; Cerutti, F.; Comas, P.; Coyle, P.; Drevermann, H.; Forty, R. W.; Frank, M.; Hagelberg, R.; Harvey, J.; Janot, P.; Jost, B.; Kneringer, E.; Knobloch, J.; Lehraus, I.; Lutters, G.; Martin, E. B.; Mato, P.; Minten, A.; Miquel, R.; Mir, Ll. M.; Moneta, L.; Oest, T.; Pacheco, A.; Pusztaszeri, J.-F.; Ranjard, F.; Rensing, P.; Rizzo, G.; Rolandi, L.; Schlatter, D.; Schmelling, M.; Schmitt, M.; Schneider, O.; Tejessy, W.; Tomalin, I. R.; Venturi, A.; Wachsmuth, H.; Wagner, A.; Ajaltouni, Z.; Barrès, A.; Boyer, C.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Rosnet, P.; Rossignol, J.-M.; Fearnley, T.; Hansen, J. B.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Nilsson, B. S.; Rensch, B.; Wäänänen, A.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Bourdon, P.; Rougé, A.; Rumpf, M.; Valassi, A.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Focardi, E.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Jaffe, D. E.; Antonelli, A.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Casper, D.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Curtis, L.; Dorris, S. J.; Halley, A. W.; Knowles, I. G.; Lynch, J. G.; O'Shea, V.; Raine, C.; Reeves, P.; Scarr, J. M.; Smith, K.; Teixeira-Dias, P.; Thompson, A. S.; Thomson, F.; Thorn, S.; Turnbull, R. M.; Becker, U.; Geweniger, C.; Graefe, G.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E. E.; Putzer, A.; Schmidt, M.; Sommer, J.; Stenzel, H.; Tittel, K.; Werner, S.; Wunsch, M.; Abbaneo, D.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Dornan, P. J.; Moutoussi, A.; Nash, J.; Sedgbeer, J. K.; Stacey, A. M.; Williams, M. D.; Dissertori, G.; Girtler, P.; Kuhn, D.; Rudolph, G.; Betteridge, A. P.; Bowdery, C. K.; Colrain, P.; Crawford, G.; Finch, A. J.; Foster, F.; Hughes, G.; Sloan, T.; Williams, M. I.; Galla, A.; Giehl, I.; Greene, A. M.; Hoffmann, C.; Jakobs, K.; Kleinknecht, K.; Quast, G.; Renk, B.; Rohne, E.; Sander, H.-G.; van Gemmeren, P.; Zeitnitz, C.; Aubert, J. J.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Bujosa, G.; Calvet, D.; Carr, J.; Diaconu, C.; Etienne, F.; Konstantinidis, N.; Payre, P.; Rousseau, D.; Talby, M.; Sadouki, A.; Thulasidas, M.; Trabelsi, K.; Aleppo, M.; Ragusa, F.; Bauer, C.; Berlich, R.; Blum, W.; Büscher, V.; Dietl, H.; Dydak, F.; Ganis, G.; Gotzhein, C.; Kroha, H.; Lütjens, G.; Lutz, G.; Männer, W.; Moser, H.-G.; Richter, R.; Rosado-Schlosser, A.; Schael, S.; Settles, R.; Seywerd, H.; Denis, R. St.; Stenzel, H.; Wiedenmann, W.; Wolf, G.; Boucrot, J.; Callot, O.; Choi, Y.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Höcker, A.; Jacholkowska, A.; Jacquet, M.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Nikolic, I.; Park, H. J.; Schune, M.-H.; Simion, S.; Veillet, J.-J.; Videau, I.; Zerwas, D.; Azzurri, P.; Bagliesi, G.; Batignani, G.; Bettarini, S.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Ciulli, V.; Dell'Orso, R.; Fantechi, R.; Ferrante, I.; Foà, L.; Forti, F.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Sanguinetti, G.; Sciabà, A.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Vannini, C.; Verdini, P. G.; Blair, G. A.; Bryant, L. M.; Chambers, J. T.; Gao, Y.; Green, M. G.; Medcalf, T.; Perrodo, P.; Strong, J. A.; von Wimmersperg-Toeller, J. H.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Haywood, S.; Maley, P.; Norton, P. R.; Thompson, J. C.; Wright, A. E.; Bloch-Devaux, B.; Colas, P.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Perez, P.; Rander, J.; Renardy, J.-F.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Trabelsi, A.; Vallage, B.; Black, S. N.; Dann, J. H.; Johnson, R. P.; Kim, H. Y.; Litke, A. M.; McNeil, M. A.; Taylor, G.; Booth, C. N.; Boswell, R.; Brew, C. A. J.; Cartwright, S.; Combley, F.; Koksal, A.; Letho, M.; Newton, W. M.; Reeve, J.; Thompson, L. F.; Böhrer, A.; Brandt, S.; Cowan, G.; Grupen, C.; Minguet-Rodriguez, J.; Rivera, F.; Saraiva, P.; Smolik, L.; Stephan, F.; Apollonio, M.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Musolino, G.; Rothberg, J.; Wasserbaech, S.; Armstrong, S. R.; Elmer, P.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; González, S.; Grahl, J.; Greening, T. C.; Hayes, O. J.; Hu, H.; McNamara, P. A.; Nachtman, J. M.; Orejudos, W.; Pan, Y. B.; Saadi, Y.; Scott, I. J.; Walsh, A. M.; Walsh, J.; Wu, Sau Lan; Wu, X.; Yamartino, J. M.; Zheng, M.; Zobernig, G.; Aleph Collaboration

    1996-02-01

    The inclusive production of charmed particles in Z → b overlineb decays has been measured from the yield of D0, D+, Ds+ and Λc+ decays in a sample of q overlineq events with high b purity collected with the ALEPH detector from 1992 to 1995. From these measurements, adding the charmonia production rate and an estimate of the charmed strange baryon contribution, the average number of charm quarks per b decay is determined to be nc = 1.230 ± 0.036 ± 0.038 ± 0.053, where the uncertainties are due to statistics, systematic effects and branching ratios, respectively.

  3. Decays of the b quark

    International Nuclear Information System (INIS)

    Thorndike, E.H.; Poling, R.A.

    1988-01-01

    Recent experimental results on the decay of b-flavored hadrons are reviewed. Substantial progress has been made in the study of exclusive and inclusive B-meson decays, as well as in the theoretical understanding of these processes. The two most prominent developments are the continuing failure to observe evidence of decays of the b quark to a u quark rather than a c quark, and the surprisingly high level of B 0 -anti B 0 mixing which has recently been reported by the ARGUS collaboration. Notwithstanding these results, we conclude that the health of the Standard Model is excellent. (orig.)

  4. Decay heat uncertainty quantification of MYRRHA

    Directory of Open Access Journals (Sweden)

    Fiorito Luca

    2017-01-01

    Full Text Available MYRRHA is a lead-bismuth cooled MOX-fueled accelerator driven system (ADS currently in the design phase at SCK·CEN in Belgium. The correct evaluation of the decay heat and of its uncertainty level is very important for the safety demonstration of the reactor. In the first part of this work we assessed the decay heat released by the MYRRHA core using the ALEPH-2 burnup code. The second part of the study focused on the nuclear data uncertainty and covariance propagation to the MYRRHA decay heat. Radioactive decay data, independent fission yield and cross section uncertainties/covariances were propagated using two nuclear data sampling codes, namely NUDUNA and SANDY. According to the results, 238U cross sections and fission yield data are the largest contributors to the MYRRHA decay heat uncertainty. The calculated uncertainty values are deemed acceptable from the safety point of view as they are well within the available regulatory limits.

  5. Cluster decay of 218U isotope

    International Nuclear Information System (INIS)

    Shivakumaraswamy, G.; Umesh, T.K.

    2012-01-01

    The phenomenon of spontaneous emission of charged particles heavier than alpha particle and lighter than a fission fragment from radioactive nuclei without accompanied by the emission of neutrons is known as cluster radioactivity or exotic radioactivity. The process of emission of charged particles heavier than alpha particle and lighter than a fission fragment is called exotic decay or cluster decay. The phenomenon of cluster radioactivity was first predicted theoretically by Sandulescu et al in 1980. Rose and Jones made first experimental observations of 14 C emission from 223 Ra in 1984. Several cluster decay modes in trans-lead region have been experimentally observed. The half-life values for different modes of cluster decay from different isotopes of uranium have been calculated using different theoretical models such as the analytical super asymmetric model (ASAFM), Preformed cluster model (PCM) and Coulomb and Proximity potential model (CPPM) etc. Recently some semi-empirical formulae, i.e, single line of universal curve (UNIV), Universal decay law (UDL) for both alpha and cluster radioactivity have also been proposed to explain cluster decay data. The alpha decay half-life of 218-219 U isotopes has been experimentally measured in 2007. The half-life values for different cluster decay modes of 218 U isotopes have been calculated PCM model. Recently in 2011, the half-life values have also been calculated for some cluster decay modes of 222-236 U isotopes using the effective liquid drop description with the varying mass asymmetry (VMAS) shape and effective inertial coefficient. In the light of this, in the present work we have studied the cluster radioactivity of 218 U isotope. The logarithmic half-lives for few cluster decay modes from 218 U isotope have been calculated by using three different approaches, i.e, UNIV proposed by Poenaru et al in 2011, UDL proposed by Qi et al in 2009 and the CPPM model proposed by Santhosh et al in 2002. The CPPM based

  6. Detailed α -decay study of 180Tl

    Science.gov (United States)

    Andel, B.; Andreyev, A. N.; Antalic, S.; Barzakh, A.; Bree, N.; Cocolios, T. E.; Comas, V. F.; Diriken, J.; Elseviers, J.; Fedorov, D. V.; Fedosseev, V. N.; Franchoo, S.; Ghys, L.; Heredia, J. A.; Huyse, M.; Ivanov, O.; Köster, U.; Liberati, V.; Marsh, B. A.; Nishio, K.; Page, R. D.; Patronis, N.; Seliverstov, M. D.; Tsekhanovich, I.; Van den Bergh, P.; Van De Walle, J.; Van Duppen, P.; Venhart, M.; Vermote, S.; Veselský, M.; Wagemans, C.

    2017-11-01

    A detailed α -decay spectroscopy study of 180Tl has been performed at ISOLDE (CERN). Z -selective ionization by the Resonance Ionization Laser Ion Source (RILIS) coupled to mass separation provided a high-purity beam of 180Tl. Fine-structure α decays to excited levels in the daughter 176Au were identified and an α -decay scheme of 180Tl was constructed based on an analysis of α -γ and α -γ -γ coincidences. Multipolarities of several γ -ray transitions deexciting levels in 176Au were determined. Based on the analysis of reduced α -decay widths, it was found that all α decays are hindered, which signifies a change of configuration between the parent and all daughter states.

  7. Streamer chamber: pion decay

    CERN Multimedia

    1992-01-01

    The real particles produced in the decay of a positive pion can be seen in this image from a streamer chamber. Streamer chambers consist of a gas chamber through which a strong pulsed electric field is passed, creating sparks as a charged particle passes through it. A magnetic field is added to cause the decay products to follow curved paths so that their charge and momentum can be measured.

  8. Decay property of Timoshenko system in thermoelasticity

    KAUST Repository

    Said-Houari, Belkacem

    2011-12-30

    We investigate the decay property of a Timoshenko system of thermoelasticity in the whole space for both Fourier and Cattaneo laws of heat conduction. We point out that although the paradox of infinite propagation speed inherent in the Fourier law is removed by changing to the Cattaneo law, the latter always leads to a solution with the decay property of the regularity-loss type. The main tool used to prove our results is the energy method in the Fourier space together with some integral estimates. We derive L 2 decay estimates of solutions and observe that for the Fourier law the decay structure of solutions is of the regularity-loss type if the wave speeds of the first and the second equations in the system are different. For the Cattaneo law, decay property of the regularity-loss type occurs no matter what the wave speeds are. In addition, by restricting the initial data to U 0∈H s(R)∩L 1,γ(R) with a suitably large s and γ ∈ [0,1], we can derive faster decay estimates with the decay rate improvement by a factor of t -γ/2. © 2011 John Wiley & Sons, Ltd.

  9. Ring current proton decay by charge exchange

    Science.gov (United States)

    Smith, P. H.; Hoffman, R. A.; Fritz, T.

    1975-01-01

    Explorer 45 measurements during the recovery phase of a moderate magnetic storm have confirmed that the charge exchange decay mechanism can account for the decay of the storm-time proton ring current. Data from the moderate magnetic storm of 24 February 1972 was selected for study since a symmetrical ring current had developed and effects due to asymmetric ring current losses could be eliminated. It was found that after the initial rapid decay of the proton flux, the equatorially mirroring protons in the energy range 5 to 30 keV decayed throughout the L-value range of 3.5 to 5.0 at the charge exchange decay rate calculated by Liemohn. After several days of decay, the proton fluxes reached a lower limit where an apparent equilibrium was maintained, between weak particle source mechanisms and the loss mechanisms, until fresh protons were injected into the ring current region during substorms. While other proton loss mechanisms may also be operating, the results indicate that charge exchange can entirely account for the storm-time proton ring current decay, and that this mechanism must be considered in all studies involving the loss of proton ring current particles.

  10. Aspects of radiative K+e3 decays

    International Nuclear Information System (INIS)

    Kubis, B.; Mueller, E.H.; Gasser, J.; Schmid, M.

    2007-01-01

    We re-investigate the radiative charged kaon decay K ± →π 0 e ± ν e γ [K e3γ ± ] in chiral perturbation theory, merging the chiral expansion with Low's theorem. We thoroughly analyze the precision of the predicted branching ratio relative to the non-radiative decay channel. Structure dependent terms and their impact on differential decay distributions are investigated in detail, and the possibility to see effects of the chiral anomaly in this decay channel is emphasized. (orig.)

  11. Decay of psi (3684) into psi (3095)

    International Nuclear Information System (INIS)

    Abrams, G.S.; Briggs, D.D.; Chinowsky, W.; Friedberg, C.E.; Goldhaber, G.; Kadyk, J.A.; Litke, A.M.; Lulu, B.A.; Pierre, F.M.; Sadoulet, B.; Trilling, G.H.; Whitaker, J.S.; Wiss, J.E.; Zipse, J.E.; Boyarski, A.M.; Breidenbach, M.; Bulos, F.; Feldman, G.J.; Fischer, G.E.; Fryberger, D.; Hanson, G.; Jean-Marie, B.; Larsen, R.R.; Luth, V.; Lynch, H.L.; Lyon, D.; Morehouse, C.C.; Paterson, J.M.; Perl, M.L.; Rapidis, P.; Richter, B.; Schwitters, R.F.; Tanenbaum, W.; Vannucci, F.

    1975-01-01

    We observe psi (3684) to decay into psi (3095) with a branching ratio of 0.57plus-or-minus0.08. The branching ratio for the particular decay mode psi (3095)+π + +π - is measured to be 0.32plus-or-minus0.04. Remaining decays leading to psi (3095) are largely, but not entirely, accounted for by the mode psi (3095)+π 0 +π 0 if the two pions in this decay are in a state of zero isospin

  12. Decay Spectroscopy for Nuclear Astrophysics: {beta}-delayed Proton Decay

    Energy Technology Data Exchange (ETDEWEB)

    Trache, L.; Simmons, E.; Spiridon, A.; McCleskey, M.; Roeder, B. T.; Tribble, R. E. [Texas A and M University, College Station, TX 77845 (United States); Saastamoinen, A.; Jokinen, A.; Aysto, J. [University of Jyvaskyla, Jyvaskyla (Finland); Davinson, T.; Woods, P. J. [University of Edinburgh, Edinburgh (United Kingdom); Pollacco, E.; Kebbiri, M. [CEA/IRFU Saclay (France); Pascovici, G. [IKP, Universitaet zu Koeln (Germany)

    2011-11-30

    Decay spectroscopy is one of the oldest indirect methods in nuclear astrophysics. We have developed at TAMU techniques to measure beta- and beta-delayed proton decay of sd-shell, proton-rich nuclei. The short-lived radioactive species are produced in-flight, separated, then slowed down (from about 40 MeV/u) and implanted in the middle of very thin Si detectors. These allowed us to measure protons with energies as low as 200 keV from nuclei with lifetimes of 100 ms or less. At the same time we measure gamma-rays up to 8 MeV with high resolution HPGe detectors. We have studied the decay of {sup 23}Al, {sup 27}P, {sup 31}Cl, all important for understanding explosive H-burning in novae. The technique has shown a remarkable selectivity to beta-delayed charged-particle emission and works even at radioactive beam rates of a few pps. The states populated are resonances for the radiative proton capture reactions {sup 22}Na(p,{gamma}){sup 23}Mg(crucial for the depletion of {sup 22}Na in novae), {sup 26m}Al(p,{gamma}){sup 27}Si and {sup 30}P(p,{gamma}){sup 31}S(bottleneck in novae and XRB burning), respectively. More recently we have radically improved the technique using a gas based detector we call AstroBox.

  13. Reinvestigation of 56Ni decay

    International Nuclear Information System (INIS)

    Sur, B.; Norman, E.B.; Lesko, K.T.; Browne, E.; Larimer, R.

    1990-01-01

    In a series of experiments, we have reinvestigated the decay of the doubly magic nucleus 56 Ni, which is believed to be copiously produced in supernovae. We have confirmed its previously known decay scheme and half-life, and have searched for several rare decay modes. We establish an upper limit of 5.8x10 -7 for the branching ratio of the second forbidden unique β + decay to the 158-keV level in 56 Co, leading to a lower limit of 2.9x10 4 yr for the half-life of fully ionized 56 Ni nuclei in cosmic rays. We also establish an upper limit of 5.0x10 -3 for the branching ratio of the isospin forbidden Fermi electron capture transition to the 1451-keV level in 56 Co, which in turn leads to an upper limit of 124 keV for the isospin mixing Coulomb matrix element of the 56 Ni ground state

  14. Limits on rare exclusive decays of B mesons

    International Nuclear Information System (INIS)

    Avery, P.; Besson, D.; Bowcock, T.; Giles, R.T.; Hassard, J.; Kinoshita, K.; Pipkin, F.M.; Wilson, R.; Wolinski, J.; Xiao, D.; Gentile, T.; Haas, P.; Hempstead, M.; Jensen, T.; Kagan, H.; Kass, R.; Behrends, S.; Guida, J.M.; Guida, J.A.; Morrow, F.; Poling, R.; Thorndike, E.H.; Tipton, P.; Alam, M.S.; Katayama, N.; Kim, I.J.; Sun, C.R.; Tanikella, V.; Bortoletto, D.; Chen, A.; Garren, L.; Goldberg, M.; Holmes, R.; Horwitz, N.; Jawahery, A.; Lubrano, P.; Moneti, G.C.; Sharma, V.; Csorna, S.E.; Mestayer, M.D.; Panvini, R.S.; Word, G.B.; Bean, A.; Bobbink, G.J.; Brock, I.C.; Engler, A.; Ferguson, T.; Kraemer, R.W.; Rippich, C.; Vogel, H.; Bebek, C.; Berkelman, K.; Blucher, E.; Cassel, D.G.; Copie, T.; DeSalvo, R.; DeWire, J.W.; Ehrlich, R.; Galik, R.S.; Gilchriese, M.G.D.; Gittelman, B.; Gray, S.W.; Halling, A.M.; Hartill, D.L.; Heltsley, B.K.; Holzner, S.; Ito, M.; Kandaswamy, J.; Kowalewski, R.; Kreinick, D.L.; Kubota, Y.; Mistry, N.B.; Mueller, J.; Namjoshi, R.; Nordberg, E.; Ogg, M.; Perticone, D.; Peterson, D.; Pisharody, M.; Read, K.; Riley, D.; Silverman, A.; Stone, S.; Yi Xia; Sadoff, A.J.

    1987-01-01

    We have set upper limits for rare exclusive decays of B mesons arising from higher order processes in the standard model of electroweak interactions. Such decays may occur via ''penguin diagrams'' in B decay. We also set an upper limit on a lepton-number-violating decay mode of the neutral B meson. (orig.)

  15. Radioactive decay data tables: A handbook of decay data for application to radiation dosimetry and radiological assessments

    Science.gov (United States)

    Kocher, D. C.; Smith, J. S.

    Decay data are presented for approximately 500 radionuclides including those occurring naturally in the environment, those of potential importance in routine or accidental releases from the nuclear fuel cycle, those of current interest in nuclear medicine and fusion reactor technology, and some of those of interest to Committee 2 of the International Commission on Radiological Protection for the estimation of annual limits on intake via inhalation and ingestion for occupationally exposed individuals. Physical processes involved in radioactive decay which produce the different types of radiation observed, methods used to prepare the decay data sets for each radionuclide in the format of the computerized evaluated nuclear structure data file, the tables of radioactive decay data, and the computer code MEDLIST used to produce the tables are described. Applications of the data to problems of interest in radiation dosimetry and radiological assessments are considered as well as the calculations of the activity of a daughter radionuclide relative to the activity of its parent in a radioactive decay chain.

  16. Search for charged Higgs boson decays of the top quark using hadronic τ decays

    International Nuclear Information System (INIS)

    Abe, F.; Akimoto, H.; Akopian, A.; Albrow, M.G.; Amendolia, S.R.; Amidei, D.; Antos, J.; Anway-Wiese, C.; Aota, S.; Apollinari, G.; Asakawa, T.; Ashmanskas, W.; Atac, M.; Auchincloss, P.; Azfar, F.; Azzi-Bacchetta, P.; Bacchetta, N.; Badgett, W.; Bagdasarov, S.; Bailey, M.W.; Bao, J.; de Barbaro, P.; Barbaro-Galtieri, A.; Barnes, V.E.; Barnett, B.A.; Bauer, G.; Baumann, T.; Bedeschi, F.; Behrends, S.; Belforte, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Benlloch, J.; Bensinger, J.; Benton, D.; Beretvas, A.; Berge, J.P.; Berryhill, J.; Bertolucci, S.; Bhatti, A.; Biery, K.; Binkley, M.; Bisello, D.; Blair, R.E.; Blocker, C.; Bodek, A.; Bokhari, W.; Bolognesi, V.; Bortoletto, D.; Boudreau, J.; Breccia, L.; Bromberg, C.; Bruner, N.; Buckley-Geer, E.; Budd, H.S.; Burkett, K.; Busetto, G.; Byon-Wagner, A.; Byrum, K.L.; Cammerata, J.; Campagnari, C.; Campbell, M.; Caner, A.; Carithers, W.; Carlsmith, D.; Castro, A.; Cauz, D.; Cen, Y.; Cervelli, F.; Chao, H.Y.; Chapman, J.; Cheng, M.; Chiarelli, G.; Chikamatsu, T.; Chiou, C.N.; Christofek, L.; Cihangir, S.; Clark, A.G.; Cobal, M.; Contreras, M.; Conway, J.; Cooper, J.; Cordelli, M.; Couyumtzelis, C.; Crane, D.; Cronin-Hennessy, D.; Culbertson, R.; Cunningham, J.D.; Daniels, T.; DeJongh, F.; Delchamps, S.; DellAgnello, S.; DellOrso, M.; Demortier, L.; Denby, B.; Deninno, M.; Derwent, P.F.; Devlin, T.; Dickson, M.; Dittmann, J.R.; Donati, S.; Done, J.; Dorigo, T.; Dunn, A.; Eddy, N.; Einsweiler, K.; Elias, J.E.; Ely, R.; Engels, E. Jr.; Errede, D.; Errede, S.; Fan, Q.; Fiori, I.; Flaugher, B.; Foster, G.W.; Franklin, M.; Frautschi, M.; Freeman, J.; Friedman, J.; Frisch, H.; Fuess, T.A.; Fukui, Y.; Funaki, S.; Gagliardi, G.; Galeotti, S.; Gallinaro, M.; Garcia-Sciveres, M.; Garfinkel, A.F.; Gay, C.; Geer, S.; Gerdes, D.W.; Giannetti, P.; Giokaris, N.; Giromini, P.; Gladney, L.; Glenzinski, D.; Gold, M.; Gonzalez, J.; Gordon, A.; Goshaw, A.T.; Goulianos, K.; Grassmann, H.; Groer, L.; Grosso-Pilcher, C.

    1996-01-01

    We present the result of a search for charged Higgs boson decays of the top quark, produced in p bar p collisions at √s=1.8 TeV. When the charged Higgs boson is heavy and decays to a τ lepton, which subsequently decays hadronically, the resulting events have a unique signature: large missing transverse energy and the low-charged-multiplicity τ. Data collected in 1992 and 1993 at the Collider Detector at Fermilab, corresponding to 18.7±0.7 pb -1 , exclude new regions of combined top quark and charged Higgs boson mass, in extensions to the standard model with two Higgs doublets. copyright 1996 The American Physical Society

  17. Charged track multiplicity in B meson decay

    International Nuclear Information System (INIS)

    Brandenburg, G.; Ershov, A.; Gao, Y. S.; Kim, D. Y.-J.; Wilson, R.; Browder, T. E.; Li, Y.; Rodriguez, J. L.; Yamamoto, H.; Bergfeld, T.

    2000-01-01

    We have used the CLEO II detector to study the multiplicity of charged particles in the decays of B mesons produced at the Υ(4S) resonance. Using a sample of 1.5x10 6 B meson pairs, we find the mean inclusive charged particle multiplicity to be 10.71±0.02 -0.15 +0.21 for the decay of the pair. This corresponds to a mean multiplicity of 5.36±0.01 -0.08 +0.11 for a single B meson. Using the same data sample, we have also extracted the mean multiplicities in semileptonic and nonleptonic decays. We measure a mean of 7.82±0.05 -0.19 +0.21 charged particles per BB(bar sign) decay when both mesons decay semileptonically. When neither B meson decays semileptonically, we measure a mean charged particle multiplicity of 11.62±0.04 -0.18 +0.24 per BB(bar sign) pair. (c) 2000 The American Physical Society

  18. Cusps in KL→3π decays

    International Nuclear Information System (INIS)

    Bissegger, M.; Fuhrer, A.; Gasser, J.; Kubis, B.; Rusetsky, A.

    2008-01-01

    The pion mass difference generates a pronounced cusp in K→3π decays, the strength of which is related to the ππ S-wave scattering lengths. We apply an effective field theory framework developed earlier to evaluate the amplitudes for K L →3π decays in a systematic manner, where the strictures imposed by analyticity and unitarity are respected automatically. The amplitudes for the decay η→3π are also given

  19. Welding the CNGS decay tube

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    3.6 km of welds were required for the 1 km long CERN Neutrinos to Gran Sasso (CNGS) decay tube, in which particles produced in the collision with a proton and a graphite target will decay into muons and muon neutrinos. Four highly skilled welders performed this delicate task.

  20. Soudan 2 nucleon decay experiment

    International Nuclear Information System (INIS)

    Thron, J.L.

    1986-01-01

    The Soudan 2 nucleon decay experiment consists of a 1.1 Kton fine grained iron tracking calorimeter. It has a very isotropic detection structure which along with its flexible trigger will allow detection of multiparticle and neutrino proton decay modes. The detector has now entered its construction stage

  1. Search for the β decay of 96Zr

    Science.gov (United States)

    Finch, S. W.; Tornow, W.

    2016-01-01

    96Zr and 48Ca are unique among double-β decay candidate nuclides in that they may also undergo single-β decay. In the case of 96Zr, the single-β decay mode is dominated by the fourth-forbidden β decay with a 119 keV Q value. A search was conducted for the β decay of 96Zr by observing the decay of the daughter 96Nb nucleus. Two coaxial high-purity germanium detectors were used in coincidence to detect the γ-ray cascade produced by the daughter nucleus as it de-excited to the ground state. The experiment was carried out at the Kimballton Underground Research Facility and produced 685.7 days of data with a 17.91 g enriched sample. No counts were seen above background, producing a limit of T1/2 > 2.4 ×1019 year. This is the first experimental search that is able to discern between the β decay and the double-β decay to an excited state of 96Zr.

  2. Heavy Flavour Production and Decay at ATLAS

    CERN Document Server

    Jones, RWL; The ATLAS collaboration

    2013-01-01

    ATLAS is taking advantage of its large integrated luminosity band sophisticated muon and dimuon triggers to make competitive measurements of heavy flavour production and decay. Inclusive production and heavy flavour jet production is discussed before turning to charm and onium production. The production and decay of individual B hadron species is then addressed, including the current best measurement of the Λb lifetime. A much improved analysis of CP related quantities in Bs decays is presented, before turning to recent results and prospects for rare B decays.

  3. Scalar-mediated double beta decay and LHC

    International Nuclear Information System (INIS)

    Gonzalez, L.; Helo, J.C.; Hirsch, M.; Kovalenko, S.G.

    2016-01-01

    The decay rate of neutrinoless double beta (0νββ) decay could be dominated by Lepton Number Violating (LNV) short-range diagrams involving only heavy scalar intermediate particles, known as “topology-II” diagrams. Examples are diagrams with diquarks, leptoquarks or charged scalars. Here, we compare the LNV discovery potentials of the LHC and 0νββ-decay experiments, resorting to three example models, which cover the range of the optimistic-pessimistic cases for 0νββ decay. We use the LHC constraints from dijet as well as leptoquark searches and find that already with 20/fb the LHC will test interesting parts of the parameter space of these models, not excluded by the current limits on 0νββ-decay.

  4. Nuclear decay data: some applications and needs

    International Nuclear Information System (INIS)

    Reich, C.W.

    1985-01-01

    Nuclear decay data have broad relevance to a number of basic scientific disciplines as well as to many areas of technology. In this paper we discuss selected applications where decay data are making, or promise to make, important contributions. The following specific illustrations are discussed: the large body of precise new actinide-nuclide decay data produced through the work of the recently concluded IAEA Coordinated Research Program on the Measurement and Evaluation of Transactinium Isotope Nuclear Decay Data; the use of actinide-nuclide half-lives as reference standards in nuclear-data measurements; and the relevance of short-lived fission-product decay data to basic physics and reactor technology and some of the problems and challenges that they present to both theory and experiment

  5. Scalar-mediated double beta decay and LHC

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, L. [Universidad Técnica Federico Santa María, Centro-Científico-Tecnológico de Valparaíso,Casilla 110-V, Valparaíso (Chile); Helo, J.C. [Universidad Técnica Federico Santa María, Centro-Científico-Tecnológico de Valparaíso,Casilla 110-V, Valparaíso (Chile); Departamento de Física, Facultad de Ciencias, Universidad de La Serena,Avenida Cisternas 1200, La Serena (Chile); Hirsch, M. [AHEP Group, Instituto de Física Corpuscular - C.S.I.C./Universitat de València,Edificio de Institutos de Paterna, Apartado 22085, E-46071 València (Spain); Kovalenko, S.G. [Universidad Técnica Federico Santa María, Centro-Científico-Tecnológico de Valparaíso,Casilla 110-V, Valparaíso (Chile)

    2016-12-23

    The decay rate of neutrinoless double beta (0νββ) decay could be dominated by Lepton Number Violating (LNV) short-range diagrams involving only heavy scalar intermediate particles, known as “topology-II” diagrams. Examples are diagrams with diquarks, leptoquarks or charged scalars. Here, we compare the LNV discovery potentials of the LHC and 0νββ-decay experiments, resorting to three example models, which cover the range of the optimistic-pessimistic cases for 0νββ decay. We use the LHC constraints from dijet as well as leptoquark searches and find that already with 20/fb the LHC will test interesting parts of the parameter space of these models, not excluded by the current limits on 0νββ-decay.

  6. Annihilation decays of bottomonium

    International Nuclear Information System (INIS)

    Monteiro, Antony Prakash; Bhat, Manjunath; D'Souza, Praveen P.; Vijaya Kumar, K.B.

    2016-01-01

    The bound state of a bottom quark b and its anti quark b-bar known as bottomonium was first seen in the spectrum of μμ"- pairs produced in 400 GeV proton-nucleus collisions at Fermilab. It was discovered as spin triplet states ϒ(1S), ϒ(2S) and ϒ(3S) by E288 collaboration at Fermilab. We have calculated annihilation decay widths of bottomonium states. The calculated decay widths are presented

  7. Decay and Transmutation of Nuclides

    CERN Document Server

    Aarnio, Pertti A

    1999-01-01

    We present a computer code DeTra which solves analytically the Bateman equations governing the decay, build-up and transmutation of radionuclides. The complexity of the chains and the number of nuclides are not limited. The nuclide production terms considered include transmutation of the nuclides inside the chain, external production, and fission. Time dependent calculations are possible since all the production terms can be re-defined for each irradiation step. The number of irradiation steps and output times is unlimited. DeTra is thus able to solve any decay and transmutation problem as long as the nuclear data i.e. decay data and production rates, or cross sections, are known.

  8. Cusp effects in meson decays

    Directory of Open Access Journals (Sweden)

    Kubis B.

    2010-04-01

    Full Text Available The pion mass difference generates a pronounced cusp in the π0 π0 invariant mass distribution of K+ → π0 π0 π+ decays. As originally pointed out by Cabibbo, an accurate measurement of the cusp may allow one to pin down the S-wave pion–pion scattering lengths to high precision. We present the non-relativistic effective field theory framework that permits to determine the structure of this cusp in a straightforward manner, including the effects of radiative corrections. Applications of the same formalism to other decay channels, in particular η and η′ decays, are also discussed.

  9. Semileptonic B-meson decays in SU(3)

    International Nuclear Information System (INIS)

    Li Zuohong; Hou Yunzhi

    1994-01-01

    Based on the SU(3) approximate symmetry in the strong interaction three-body and four-body semileptonic B-meson decays are analyzed. Relations between decay rates are derived. Some of these relations may provide information on the nature of various competing dynamical effects that can occur in semileptonic B-meson decays

  10. Weak decays of new particles

    International Nuclear Information System (INIS)

    Kalmus, G.

    1982-10-01

    The present experimental situation in tau-lepton, B-meson and charmed particle decays is reviewed. Special attention is paid to new lifetime measurements and in the case of B-meson decays to the rate of b → u compared to b → c. Results are compared with theoretical expectations. (author)

  11. Predictions for the decays of radially-excited baryons

    International Nuclear Information System (INIS)

    Carlson, C.E.

    2001-01-01

    We consider decays of the lowest-lying radially excited baryons. Assuming a single-quark decay approximation, and negligible configuration mixing, we make model-independent predictions for the partial decay widths to final states with a single meson. Masses of unobserved states are predicted using an old mass formula rederived using large-N c QCD. The momentum dependence of the one-body decay amplitude is determined phenomenologically by fitting to observed decays. Comparison of these predictions to experiment may shed light on whether the Roper resonance can be interpreted as a three-quark state. (author)

  12. Quantum decay model with exact explicit analytical solution

    Science.gov (United States)

    Marchewka, Avi; Granot, Er'El

    2009-01-01

    A simple decay model is introduced. The model comprises a point potential well, which experiences an abrupt change. Due to the temporal variation, the initial quantum state can either escape from the well or stay localized as a new bound state. The model allows for an exact analytical solution while having the necessary features of a decay process. The results show that the decay is never exponential, as classical dynamics predicts. Moreover, at short times the decay has a fractional power law, which differs from perturbation quantum method predictions. At long times the decay includes oscillations with an envelope that decays algebraically. This is a model where the final state can be either continuous or localized, and that has an exact analytical solution.

  13. 152Eu decay

    International Nuclear Information System (INIS)

    Artamonova, K.P.; Vinogradov, V.M.; Grigor'ev, E.P.; Zolotavin, A.V.; Makarov, V.M.; Sergeev, V.O.; Usynko, T.M.

    1978-01-01

    The purpose of this paper is the measurement of the relative intensities of the most intensive conversion lines of 152 Eu, the determination of as reliable as possible magnitudes of the intensities of γ-quanta using all the available data on γ-radiation of 152 Eu, the measurement of the interval conversion coefficients (ICC) for the most intensive γ-transitions, the determination of the probabilities of the 152 Eu β-decays to the 152 Sm and 152 Gd levels. The conversion lines of the most intensive γ-transitions in the 152 Eu decay are studied and the corresponding ICC are measured on the beta-spectrometers of π√2 and UMB type. The balance for the γ-transitions in the 152 Sm and 152 Gd daughter nuclei are presented. This balance is used to determine the absolute intensities of γ-rays (in terms of the percentage of the 152 Eu decays) and the probabilities of β-transitions to the levels of daughter nuclei. More accurate data on γ-rays and conversion electrons obtained can be used for the calibration of gamma and beta spectrometers

  14. Iconic Decay in Schizophrenia

    OpenAIRE

    Hahn, Britta; Kappenman, Emily S.; Robinson, Benjamin M.; Fuller, Rebecca L.; Luck, Steven J.; Gold, James M.

    2010-01-01

    Working memory impairment is considered a core deficit in schizophrenia, but the precise nature of this deficit has not been determined. Multiple lines of evidence implicate deficits at the encoding stage. During encoding, information is held in a precategorical sensory store termed iconic memory, a literal image of the stimulus with high capacity but rapid decay. Pathologically increased iconic decay could reduce the number of items that can be transferred into working memory before the info...

  15. Ξ-P Scattering and STOPPED-Ξ-12C Reaction

    Science.gov (United States)

    Ahn, J. K.; Aoki, S.; Chung, K. S.; Chung, M. S.; En'yo, H.; Fukuda, T.; Funahashi, H.; Goto, Y.; Higashi, A.; Ieiri, M.; Iijima, T.; Iinuma, M.; Imai, K.; Itow, Y.; Lee, J. M.; Makino, S.; Masaike, A.; Matsuda, Y.; Matsuyama, Y.; Mihara, S.; Nagoshi, C.; Nomura, I.; Park, I. S.; Saito, N.; Sekimoto, M.; Shin, Y. M.; Sim, K. S.; Susukita, R.; Takashima, R.; Takeutchi, F.; Tlustý, P.; Weibe, S.; Yokkaichi, S.; Yoshida, K.; Yoshida, M.; Yoshida, T.; Yamashita, S.

    2000-09-01

    We report upper limits on the cross sections for the Ξ-p elastic and conversion processes based on the observation of one Ξ-p elastic scattering events with an invisible Λ decay. The cross section for the Ξ-p elastic scattering is, for simplicity, assumming an isotropic angular distribution, found to be 40 mb at 90% confidence level, whereas that for the Ξ-p → ΛΛ reaction is 11 mb at 90% confidence level. While the results on the elastic cross section give no stringent constraint on theoretical estimates, the upper limit on the conversion process suggests that the estimate of the RGM-F model prediction could be ruled out. We also report some preliminary results on the obervation of the stopped-Ξ- hyperon-nucleus interaction with respect to hypernuclear production and existence of doubly-strange H-dibaryon.

  16. Beta and muon decays

    International Nuclear Information System (INIS)

    Galindo, A.; Pascual, P.

    1967-01-01

    These notes represent a series of lectures delivered by the authors in the Junta de Energia Nuclear, during the Spring term of 1965. They were devoted to graduate students interested in the Theory of Elementary Particles. Special emphasis was focussed into the computational problems. Chapter I is a review of basic principles (Dirac equation, transition probabilities, final state interactions.) which will be needed later. In Chapter II the four-fermion punctual Interaction is discussed, Chapter III is devoted to the study of beta-decay; the main emphasis is given to the deduction of the formulae corresponding to electron-antineutrino correlation, electron energy spectrum, lifetimes, asymmetry of electrons emitted from polarized nuclei, electron and neutrino polarization and time reversal invariance in beta decay. In Chapter IV we deal with the decay of polarized muons with radiative corrections. Chapter V is devoted to an introduction to C.V.C. theory. (Author)

  17. Beta and muon decays

    Energy Technology Data Exchange (ETDEWEB)

    Galindo, A; Pascual, P

    1967-07-01

    These notes represent a series of lectures delivered by the authors in the Junta de Energia Nuclear, during the Spring term of 1965. They were devoted to graduate students interested in the Theory of Elementary Particles. Special emphasis was focussed into the computational problems. Chapter I is a review of basic principles (Dirac equation, transition probabilities, final state interactions.) which will be needed later. In Chapter II the four-fermion punctual Interaction is discussed, Chapter III is devoted to the study of beta-decay; the main emphasis is given to the deduction of the formulae corresponding to electron-antineutrino correlation, electron energy spectrum, lifetimes, asymmetry of electrons emitted from polarized nuclei, electron and neutrino polarization and time reversal invariance in beta decay. In Chapter IV we deal with the decay of polarized muons with radiative corrections. Chapter V is devoted to an introduction to C.V.C. theory. (Author)

  18. Weak interactions: muon decay

    International Nuclear Information System (INIS)

    Sachs, A.M.; Sirlin, A.

    1975-01-01

    The traditional theory of the dominant mode of muon decay is presented, a survey of the experiments which have measured the observable features of the decay is given, and those things which can be learned about the parameters and nature of the theory from the experimental results are indicated. The following aspects of the theory of muon decay are presented first: general four-fermion theory, two-component theory of the neutrino, V--A theory, two-component and V--A theories vs general four-fermion theory, intermediate-boson hypothesis, radiative corrections, radiative corrections in the intermediate-boson theory, and endpoint singularities and corrections of order α 2 . Experiments on muon lifetime, isotropic electron spectrum, total asymmetry and energy dependence of asymmetry of electrons from polarized muons, and electron polarization are described, and a summary of experimental results is given. 7 figures, 2 tables, 109 references

  19. Bottom-hadron production through top quark decay

    Energy Technology Data Exchange (ETDEWEB)

    Moosavi Nejad, Seyed Mohammad

    2009-06-15

    In this thesis we apply perturbative QCD to make precise predictions for some observables in high-energy processes involving bottom-quark. Our first application is a prediction for the energy spectrum of b-flavored hadrons in top quark decay. For that purpose we calculate at NLO the OCD corrections for bottom fragmentation in top decay. The b-quark in the top quark decay is considered once as a massless and once as a massive particle in our calculations. The difference between the differential width calculated in both cases can give us the perturbative fragmentation function of the b-quark. After that using the obtained differential widths and applying ZM-VFNS and GM-VFNS, we make some predictions for the spectrum of B-hadrons produced in top quark decay. The comparison of both approaches shows that the mass effect of the b-quark in the top quark decay is negligible. We also investigate the mass effect of B-hadron in the energy distribution obtained in the previous calculations and we show that this increases the value of the differential width when the energy taken away by the produced parton in top decay is small. Our second application is to obtain the helicity contributions of the W{sup +}-boson in the energy distribution of b-flavored hadrons in top quark decay. For this reason we study the angular decay distribution for the cascade decay of the top-quark (t{yields} b+W{sup +}({yields}e{sup +}+{nu}{sub e})). Using ZM-VFNS we make predictions for the NLO contributions of the longitudinal, the transverse-minus and the transverse-plus helicity of the W{sup +}-boson in the energy distribution of B-hadron. (orig.)

  20. Puzzling Two-Proton Decay of 67Kr

    Science.gov (United States)

    Wang, S. M.; Nazarewicz, W.

    2018-05-01

    Ground-state two-proton (2 p ) radioactivity is a rare decay mode found in a few very proton-rich isotopes. The 2 p decay lifetime and properties of emitted protons carry invaluable information on nuclear structure in the presence of a low-lying proton continuum. The recently measured 2 p decay of 67Kr turned out to be unexpectedly fast. Since 67Kr is expected to be a deformed system, we investigate the impact of deformation effects on the 2 p radioactivity. We apply the recently developed Gamow coupled-channel framework, which allows for a precise description of three-body systems in the presence of rotational and vibrational couplings. This is the first application of a three-body approach to a two-nucleon decay from a deformed nucleus. We show that deformation couplings significantly increase the 2 p decay width of 67Kr; this finding explains the puzzling experimental data. The calculated angular proton-proton correlations reflect a competition between 1 p and 2 p decay modes in this nucleus.

  1. Strange hadron decays involving e+e- pairs

    International Nuclear Information System (INIS)

    Soyeur, M.

    1996-01-01

    A high resolution, large acceptance e + e - detector like HADES coupled to intense secondary kaon beams could offer a remarkable opportunity to study at GSI both the electromagnetic and electroweak decays of strange hadrons. Such data can be very consistently interpreted using effective chiral Lagrangians based on the SU(3) x SU(3) symmetry. Of particular interest are a complete set of data on the electromagnetic form factors for the ρ,ω, φ and K* Dalitz decays, which would put very strong constraints on departures from ideal SU(3) mixings, and measurements of Dalitz decays of hyperons, whose electromagnetic structure is very much unknown. Better data on the nonleptonic radiative (e + e - ) decays of kaons would be most useful to study the strangeness changing weak currents and effects related to CP violation. A major progress in the understanding of these decays came recently from their description in chiral perturbation theory, where the chiral dynamics of Goldstone bosons is coupled to the weak and electromagnetic gauge fields. Those studies could be extended to the electroweak decays of hyperons. (author)

  2. Theoretical aspects of double beta decay

    International Nuclear Information System (INIS)

    Haxton, W.C.

    1984-01-01

    Considerable effort has been expended recently in theoretical studies of double beta decay. Much of this work has focussed on the constraints this process places on gauge theories of the weak interaction, in general, and on the neutrino mass matrix, in particular. In addition, interesting nuclear structure questions have arisen in studies of double beta decay matrix elements. After briefly reviewing the theory of double beta decay, some of the progress that has been made in these areas is summarized. 25 references

  3. Techniques for the treatment of IR divergences in decay processes at NLO and application to the top-quark decay.

    Science.gov (United States)

    Basso, Lorenzo; Dittmaier, Stefan; Huss, Alexander; Oggero, Luisa

    We present the extension of two general algorithms for the treatment of infrared singularities arising in electroweak corrections to decay processes at next-to-leading order: the dipole subtraction formalism and the one-cutoff slicing method. The former is extended to the case of decay kinematics which has not been considered in the literature so far. The latter is generalised to production and decay processes with more than two charged particles, where new "surface" terms arise. Arbitrary patterns of massive and massless external particles are considered, including the treatment of infrared singularities in dimensional or mass regularisation. As an application of the two techniques we present the calculation of the next-to-leading order QCD and electroweak corrections to the top-quark decay width including all off-shell and decay effects of intermediate [Formula: see text] bosons. The result, e.g., represents a building block of a future calculation of NLO electroweak effects to off-shell top-quark pair ([Formula: see text]) production. Moreover, this calculation can serve as the first step towards an event generator for top-quark decays at next-to-leading order accuracy, which can be used to attach top-quark decays to complicated many-particle top-quark processes, such as for [Formula: see text] or [Formula: see text].

  4. Decays of the vector glueball

    Science.gov (United States)

    Giacosa, Francesco; Sammet, Julia; Janowski, Stanislaus

    2017-06-01

    We calculate two- and three-body decays of the (lightest) vector glueball into (pseudo)scalar, (axial-)vector, as well as pseudovector and excited vector mesons in the framework of a model of QCD. While absolute values of widths cannot be predicted because the corresponding coupling constants are unknown, some interesting branching ratios can be evaluated by setting the mass of the yet hypothetical vector glueball to 3.8 GeV as predicted by quenched lattice QCD. We find that the decay mode ω π π should be one of the largest (both through the decay chain O →b1π →ω π π and through the direct coupling O →ω π π ). Similarly, the (direct and indirect) decay into π K K*(892 ) is sizable. Moreover, the decays into ρ π and K*(892 )K are, although subleading, possible and could play a role in explaining the ρ π puzzle of the charmonium state ψ (2 S ) thanks to a (small) mixing with the vector glueball. The vector glueball can be directly formed at the ongoing BESIII experiment as well as at the future PANDA experiment at the FAIR facility. If the width is sufficiently small (≲100 MeV ) it should not escape future detection. It should be stressed that the employed model is based on some inputs and simplifying assumptions: the value of glueball mass (at present, the quenched lattice value is used), the lack of mixing of the glueball with other quarkonium states, and the use of few interaction terms. It then represents a first step toward the identification of the main decay channels of the vector glueball, but shall be improved when corresponding experimental candidates and/or new lattice results will be available.

  5. Formation of a Ξ-hypernucleus and transitions to double-Λ states

    International Nuclear Information System (INIS)

    Ikeda, Kiyomi; Takahashi, Miho; Fukuda, Tomokazu; Motoba, Toshio; Yamamoto, Yasuo.

    1993-06-01

    A scenario is given for the formation of Ξ - states and the transitions to states with double-Λ in anticipation of observations, especially in the KEK-E224 experiment. First, the production cross sections of Ξ - hypernuclear states by (K - , K + ) reactions are calculated within the framework of the distorted-wave impulse approximation. Next, the transition rates from Ξ - hypernuclear states to possible double-Λ states are obtained, which are closely related to single- and double-Λ emissions after the Ξ - p→ΛΛ conversion in nuclei. (author)

  6. 238Pu - Comments on Evaluation of Decay Data

    International Nuclear Information System (INIS)

    Chechev, V. P.

    2013-01-01

    This evaluation was done originally in March 2003, corrected in June 2004, and then updated in June 2009 with a literature cut-off by the same date. Decay Scheme: The decay scheme is based on 2007Br04. Some expected weak gamma-ray transitions were not observed directly in 238 Pu α-decay but have been adopted from decay of 234 Pa and 234 Np

  7. Galactic signatures of decaying dark matter

    International Nuclear Information System (INIS)

    Zhang, Le; Sigl, Guenter

    2009-05-01

    If dark matter decays into electrons and positrons, it can affect Galactic radio emissions and the local cosmic ray fluxes. We propose a new, more general analysis of constraints on dark matter. The constraints can be obtained for any decaying dark matter model by convolving the specific dark matter decay spectrum with a response function. We derive this response function from full-sky radio surveys at 408 MHz, 1.42 GHz and 23 GHz, as well as from the positron flux recently reported by PAMELA. We discuss the influence of astrophysical uncertainties on the response function, such as from propagation and from the profiles of the dark matter and the Galactic magnetic field. As an application, we find that some widely used dark matter decay scenarios can be ruled out under modest assumptions. (orig.)

  8. Galactic signatures of decaying dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Le; Sigl, Guenter [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; Redondo, Javier [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2009-05-15

    If dark matter decays into electrons and positrons, it can affect Galactic radio emissions and the local cosmic ray fluxes. We propose a new, more general analysis of constraints on dark matter. The constraints can be obtained for any decaying dark matter model by convolving the specific dark matter decay spectrum with a response function. We derive this response function from full-sky radio surveys at 408 MHz, 1.42 GHz and 23 GHz, as well as from the positron flux recently reported by PAMELA. We discuss the influence of astrophysical uncertainties on the response function, such as from propagation and from the profiles of the dark matter and the Galactic magnetic field. As an application, we find that some widely used dark matter decay scenarios can be ruled out under modest assumptions. (orig.)

  9. Higgs scalar in heavy-vector-meson decays

    International Nuclear Information System (INIS)

    Frampton, P.H.; Wada, W.W.

    1979-01-01

    For both UPSILON (9.5,b-barb) and T (t-bart), the decay into Higgs scalar plus photon is calculated, employing a triangle-diagram estimate for the dependence of this decay matrix element on the Higgs-scalar mass. This mass dependence gives a significant supression, but the decay should still be readily observable, if energetically allowed

  10. A simple decay-spectroscopy station at CRIS-ISOLDE

    Energy Technology Data Exchange (ETDEWEB)

    Lynch, K.M., E-mail: kara.marie.lynch@cern.ch [KU Leuven, Instituut voor Kern, en Stralingsfysica, BE-3001 Leuven (Belgium); EP Department, CERN, CH-1211 Geneva 23 (Switzerland); Cocolios, T.E. [KU Leuven, Instituut voor Kern, en Stralingsfysica, BE-3001 Leuven (Belgium); School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL (United Kingdom); Althubiti, N. [School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL (United Kingdom); Farooq-Smith, G.J. [KU Leuven, Instituut voor Kern, en Stralingsfysica, BE-3001 Leuven (Belgium); School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL (United Kingdom); Gins, W. [KU Leuven, Instituut voor Kern, en Stralingsfysica, BE-3001 Leuven (Belgium); Smith, A.J. [School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL (United Kingdom)

    2017-02-01

    A new decay-spectroscopy station (DSS2.0) has been designed by the CRIS collaboration for use at the radioactive ion beam facility, ISOLDE. With the design optimised for both charged-particle and γ-ray detection, the DDS2.0 allows high-efficiency decay spectroscopy to be performed. The DSS2.0 complements the existing decay-spectroscopy system at the CRIS experiment, and together provide the ability to perform laser-assisted nuclear decay spectroscopy on both ground state and long-lived isomeric species. This paper describes the new decay-spectroscopy station and presents the characterisation studies that have recently been performed.

  11. Factorization in B→Vγ decays

    International Nuclear Information System (INIS)

    Becher, T.; Hill, R. J.; Neubert, M.

    2005-01-01

    The factorization properties of the radiative decays B→Vγ are analyzed at leading order in 1/m b using the soft-collinear effective theory. It is shown that the decay amplitudes can be expressed in terms of a B→V form factor evaluated at q 2 =0, light-cone distribution amplitudes of the B and V mesons, and calculable hard-scattering kernels. The renormalization-group equations in the effective theory are solved to resum perturbative logarithms of the different scales in the decay process. Phenomenological implications for the B→K*γ branching ratio, isospin asymmetry, and CP asymmetries are discussed, with particular emphasis on possible effects from physics beyond the standard model

  12. The search for proton decay

    International Nuclear Information System (INIS)

    Haines, T.; Kaneyuki, K.; McGrew, C.; Mohapatra, R.; Peterson, E.; Cline, D.B.

    1994-01-01

    The conservation of the quantum number called baryon number, like lepton (or family) number, is an empirical fact even though there are very good reasons to expect otherwise. Experimentalists have been searching for baryon number violating decays of the proton and neutron for decades now without success. Theorists have evolved deep understanding of the relationship between the natural forces in the development of various Grand Unified Theories (GUTs) that nearly universally predict baryon number violating proton decay, or related phenomena like n-bar n oscillations. With this in mind, the Proton Decay Working Group reviewed the current experimental and theoretical status of the search for baryon number violation with an eye to the advancement in the next decade

  13. B decays, an introductory survey

    International Nuclear Information System (INIS)

    Le Yaouanc, A.; Oliver, L.; Pene, O.; Raynal, J.C.

    1994-01-01

    Some basic important theoretical tools which are currently used in b physics are overviewed. Heavy Quark Symmetry and its consequences for heavy to heavy and heavy to light semi-leptonic decays, as well as for leptonic decays, are briefly summarised. It is stressed that symmetry must be completed with dynamical calculations. A critical discussion of the nearest pole dominance (VMD) assumption is performed. Parton model and its higher twist corrections are discussed on the example of lifetimes. Finally, non-leptonic decays are considered via the example of the exclusive calculation of ΔΓ in the B s -B s -bar system. The popular factorization assumption is discussed and seems to be rather good. (author). 19 refs

  14. Mirror decay of $^{75}$Sr

    CERN Document Server

    Huikari, J; Algora, A; Cederkäll, J; Courtin, S; Dessagne, P; Fraile-Prieto, L M; Franchoo, S; Fynbo, H O U; Huang Wan Xia; Jokinen, A; Knipper, A; Maréchal, F; Miehé, C; Nácher, E; Peräjärvi, K; Poirier, E; Weissman, L; Äystö, J

    2003-01-01

    The beta -decay of /sup 75/Sr to its mirror nucleus /sup 75/Rb was studied at the ISOLDE PSB facility at CERN by means of beta -delayed gamma and proton spectroscopy. The decay Q-value and beta -delayed gamma intensity were measured for the first time. These results, 10.60+or-0.22 MeV and 4.5/sub -0.7//sup +1.9/%, together with accurate measurements of the beta -decay half-life and beta -delayed proton branching ratio yielded the Gamow-Teller strength 0.35+or-0.05 for the mirror transition. Implications of the results on studies of deformation effects and on the path of the rapid proton capture process are discussed. (24 refs).

  15. Rare decays of neutral π and eta

    International Nuclear Information System (INIS)

    Poutissou, J.M.

    1983-09-01

    The decays of the pseudoscalar neutral mesons π degree and eta degree have provided a test of fundamental principles. The main branch, π degree → 2γ, was investigated in the late 60's in the context of current algebra and the decay rate calculated from the singular triangle diagram is in excellent agreement with experiment. Rare leptonic decays of the neutral pseudoscalar mesons are of interest because of the information they reveal about neutral currents or other exotic interactions between leptons and quarks. The author discusses recent information on the π degree → e + e - decay

  16. On the Muon Decay Parameters

    CERN Document Server

    Chizhov, M V

    1996-01-01

    Predictions for the muon decay spectrum are usually derived from the derivative-free Hamiltonian. However, it is not the most general form of the possible interactions. Additional simple terms with derivatives can be introduced. In this work the distortion of the standard energy and angular distribution of the electrons in polarized muon decay caused by these terms is presented.

  17. Magnetic field decay in model SSC dipoles

    International Nuclear Information System (INIS)

    Gilbert, W.S.; Althaus, R.F.; Barale, P.J.; Benjegerdes, R.W.; Green, M.A.; Green, M.I.; Scanlan, R.M.

    1988-08-01

    We have observed that some of our model SSC dipoles have long time constant decays of the magnetic field harmonics with amplitudes large enough to result in significant beam loss, if they are not corrected. The magnets were run at constant current at the SSC injection field level of 0.3 tesla for one to three hours and changes in the magnetic field were observed. One explanation for the observed field decay is time dependent superconductor magnetization. Another explanation involves flux creep or flux flow. Data are presented on how the decay changes with previous flux history. Similar magnets with different Nb-Ti filament spacings and matrix materials have different long time field decay. A theoretical model using proximity coupling and flux creep for the observed field decay is discussed. 10 refs., 5 figs., 2 tabs

  18. Bubble chamber: Omega production and decay

    CERN Multimedia

    1973-01-01

    This image is of real particle tracks taken from the CERN 2 m liquid hydrogen bubble chamber and shows the production and decay of a negative omega particle. A negative kaon enters the chamber which decays into many particles, including a negative omega that travels a short distance before decaying into more particles. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that had been heated to boiling point.

  19. Decay heat uncertainty quantification of MYRRHA

    OpenAIRE

    Fiorito Luca; Buss Oliver; Hoefer Axel; Stankovskiy Alexey; Eynde Gert Van den

    2017-01-01

    MYRRHA is a lead-bismuth cooled MOX-fueled accelerator driven system (ADS) currently in the design phase at SCK·CEN in Belgium. The correct evaluation of the decay heat and of its uncertainty level is very important for the safety demonstration of the reactor. In the first part of this work we assessed the decay heat released by the MYRRHA core using the ALEPH-2 burnup code. The second part of the study focused on the nuclear data uncertainty and covariance propagation to the MYRRHA decay hea...

  20. Tau decays into kaons

    International Nuclear Information System (INIS)

    Finkemeier, M.; Mirkes, E.

    1995-04-01

    Predictions for semi-leptonic decay rates of the τ lepton into two meson final states and three meson final states are derived. The hadronic matrix elements are expressed in terms of form factors, which can be predicted by chiral Lagrangians supplemented by informations about all possible low-lying resonances in the different channels. Isospin symmetry relations among the different final states are carefully taken into account. The calculated brancing ratios are compared with measured decay rates where data are available

  1. Spectroscopic study of the Lambda hypernuclei by the (e,e'K+) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Miyoshi, Toshinobu [Tohoku Univ., Sendai (Japan)

    2002-01-01

    Hypernuclear spectroscopy study via the (e,e'K+) reaction has been carried out for the first time, establishing a new technique to study Lambda hypernuclei. The high quality electron beam at Jefferson Lab made it possible to measure Lambda hypernuclear spectra with an energy resolution better than 1 MeV (FWHM). The present experiment was designed to make full use of the virtual photon flux, which peaks at very forward angles, by detecting scattered electrons at 0 degrees. Scattered positive kaons were also detected near 0 degrees, where the cross section of the kaon photo-production is maximized. This unique kinematical configuration was realized with the HyperNuclear Spectrometer System (HNSS), which consisted of the Short-Orbit Spectrometer, the Enge Split-Pole Spectrometer, and the splitter magnet. The $12\\atop{Λ}$B mass spectrum was measured in the 12C(e,e'K+)$12\\atop{Λ}$ reaction with 0.9 MeV (FWHM) energy resolution. The averaged binding energy of the $12\\atop{Λ}$B ground state doublet was obtained to be 11.7 ± 0.1 (statistical) ± 0.3 (systematic) MeV, which is consistent with emulsion data. The general spectral structure of the 12C(e,e'K+) $12\\atop{Λ}$B reaction was found to be similar to that of the 12C(Λ+,K+)$12\\atop{Λ}$C reaction, showing characteristic peaks corresponding to sLambda and pLambda orbits, as well as a few core-excited states. The cross section of the $12\\atop{Λ}$B ground state doublet was derived to be 117 ± 13 (statistical) ± 14 (systematic) nb/sr. The theoretical prediction of the cross section was consistent with the present result, validating DWIA calculation for hypernuclear yields. The present study proved the effectiveness of the (e,e'K+) reaction for future Lambda hypernuclear spectroscopy studies.

  2. A phenomenological analysis of non-resonant charm meson decays

    International Nuclear Information System (INIS)

    Bediaga, I.; Goebel, C.; Mendez-Galain, R.

    1997-07-01

    We analyse the consequences of the usual assumption of a constant function to fit non-resonant decays from experimental Dalitz plot describing charmed meson decays. We first show, using the D + -> K 0 π + π 0 decay channel as an example, how an inadequate extraction of the non-resonant contribution could yield incorrect measurements for the resonant channels. We analyse how the correct study of this decay will provide a test for the validity of factorization in D meson decays. Finally, we show how form factors that can be measured from the D + s -> π - π + π + decay. We emphasize its relevance for the study of the decay τ -> v t 3π and the extraction of the α 1 meson width. (author)

  3. Form factors in Kμ3 decay

    International Nuclear Information System (INIS)

    Wilke, W.G.

    1976-01-01

    The decay of 1.83 GeV/c K + mesons in flight was studied using a magnetic spectrometer with multi-wire proportional chambers for the charged particles and an array of lead glass to detect γ-rays from π 0 decay. For the decay mode K + yields π 0 μ + nu/sub μ/ the muons were stopped after the spectrometer in a polarimeter, an array of carbon blocks and scintillators in a 40 g magnetic field. Four scintillators surrounded each carbon clock. The pattern of polarimeter counters in coincidence with the entering muon, and the pattern in coincidence with the decay positron were recorded, as well as the time delay between the μ + and the e + . For events with two γ-rays striking the lead glass, the positions and energies of the γ-rays were also recorded. Each Kμ 3 decay with two detected γ-rays was a 2-C fit, with an additional constraint of range-momentum consistency for the muon. Polarization analysis on a final sample of 24,669 events gave a value Xi(q 2 )/sub avg./ = -.25 +- .25. The experiment also gave values for Xi(q 2 ) in each of four q 2 bins

  4. Leptonic B Decays at BaBar

    Energy Technology Data Exchange (ETDEWEB)

    Monorchio, Diego; /INFN, Naples /Naples U.

    2011-09-13

    The authors will present the most recent results on leptonic B decays B{sup {+-}(0)} {yields} K*{sup {+-}(0)} {nu}{bar {nu}} and B{sup {+-}} {yields} {mu}{sup {+-}}{nu}, based on the data collected by the BaBar detector at PEP-II, an asymmetric e{sup +}e{sup -} collider at the center of mass energy of the {Upsilon}(4S) resonance. Rare B decays have always been a standard probe for New Physics (NP) searches. The very low Standard Model (SM) rate of these decays often make them unaccessible with the present experimental datasets, unless NP effects enhance the rate up to the current experimental sensitivity. Moreover, as NP effects can modify the decay kinematic, particular attention must be payed in order to perform a model independent analysis. A B-Factory provides an unique environment where to investigate these processes. The high number of B{bar B} pairs produced by a B-Factory often allows to approach the needed experimental sensitivity. Moreover, the clean environment and the closed kinematic of the initial state enable to obtaining a very pure sample where to look for these decays.

  5. Leptonic B Decays at BaBar

    Energy Technology Data Exchange (ETDEWEB)

    Baracchini, Elisabetta; /Rome U. /INFN, Rome

    2011-11-10

    We will present the most recent results on leptonic B decays B{sup {+-}(0)} {yields} K*{sup {+-}(0)}{nu}{bar {nu}} and B{sup {+-}} {yields} {mu}{sup {+-}}{nu}, based on the data collected by the BaBar detector at PEP-II, an asymmetric e{sup +}e{sup -} collider at the center of mass energy of the {Upsilon}(4S) resonance. Rare B decays have always been a standard probe for New Physics (NP) searches. The very low Standard Model (SM) rate of these decays often make them unaccessible with the present experimental datasets, unless NP effects enhance the rate up to the current experimental sensitivity. Moreover, as NP effects can modify the decay kinematic, particular attention must be paid in order to perform a model independent analysis. A B-Factory provides an unique environment to investigate these processes. The high number of B{bar B} pairs produced by a B-Factory often allows to approach the needed experimental sensitivity. Moreover, the clean environment and the closed kinematic of the initial state enable to obtaining a very pure sample where to look for these decays.

  6. Ordered kinematic endpoints for 5-body cascade decays

    Energy Technology Data Exchange (ETDEWEB)

    Klimek, Matthew D. [Theory Group, Department of Physics and Texas Cosmology Center,University of Texas at Austin, 2515 Speedway, Stop C1608, Austin, TX, 78712 (United States)

    2016-12-23

    We present expressions for the kinematic endpoints of 5-body cascade decay chains proceeding through all possible combinations of 2-body and 3-body decays, with one stable invisible particle in the final decay stage. When an invariant mass can be formed in multiple ways by choosing different final state particles from a common vertex, we introduce techniques for finding the sub-leading endpoints for all indistinguishable versions of the invariant mass. In contrast to short decay chains, where sub-leading endpoints are linearly related to the leading endpoints, we find that in 5-body decays, they provide additional independent constraints on the mass spectrum.

  7. Enhanced nuclear level decay in hot dense plasmas

    International Nuclear Information System (INIS)

    Gosselin, G.; Morel, P.

    2004-01-01

    A model of nuclear level decay in a plasma environment is described. Nuclear excitation and decay by photon processes, nuclear excitation by electron capture, and decay by internal conversion are taken into account. The electrons in the plasma are described by a relativistic average atom model for the bound electrons and by a relativistic Thomas-Fermi-Dirac model for the free electrons. Nuclear decay of isomeric level may be enhanced through an intermediate level lying above the isomer. An enhanced nuclear decay rate may occur for temperatures far below the excitation energy of the transition to the intermediate level. In most cases, the enhancement factor may reach several decades

  8. Weak decays of charmed particles and heavy leptons

    International Nuclear Information System (INIS)

    Walsh, T.F.

    1977-11-01

    Charm's chirality, cabibbo's angle in semileptonic processes, ΔC = 1 nonleptonic decay and D 0 -anti D 0 mixing and ΔC = -ΔS decays, models for nonleptonic decays and especially the properties of TAU are discussed. (BJ) [de

  9. Spectroscopy of element 115 decay chains.

    Science.gov (United States)

    Rudolph, D; Forsberg, U; Golubev, P; Sarmiento, L G; Yakushev, A; Andersson, L-L; Di Nitto, A; Düllmann, Ch E; Gates, J M; Gregorich, K E; Gross, C J; Heßberger, F P; Herzberg, R-D; Khuyagbaatar, J; Kratz, J V; Rykaczewski, K; Schädel, M; Åberg, S; Ackermann, D; Block, M; Brand, H; Carlsson, B G; Cox, D; Derkx, X; Eberhardt, K; Even, J; Fahlander, C; Gerl, J; Jäger, E; Kindler, B; Krier, J; Kojouharov, I; Kurz, N; Lommel, B; Mistry, A; Mokry, C; Nitsche, H; Omtvedt, J P; Papadakis, P; Ragnarsson, I; Runke, J; Schaffner, H; Schausten, B; Thörle-Pospiech, P; Torres, T; Traut, T; Trautmann, N; Türler, A; Ward, A; Ward, D E; Wiehl, N

    2013-09-13

    A high-resolution α, x-ray, and γ-ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum für Schwerionenforschung. Thirty correlated α-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z=115. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z>112. Comprehensive Monte Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation.

  10. Testing Lorentz invariance in β decay

    Directory of Open Access Journals (Sweden)

    Sytema A.

    2014-03-01

    Experimentally we exploit the Gamow-Teller transition of polarized 20Na, where we can test the dependence of the β-decay rate on the spin orientation of 20Na. The polarization degree is measured using the β asymmetry, while the decay rate is measured by the γ yield. A change in the γ rate, when reversing the spin, implies Lorentz invariance violation. The decay rate should depend on sidereal time and the polarization direction relative to the rotation axis of the earth. The method of the measurement will be presented, together with the first results.

  11. New definition of the decay law

    International Nuclear Information System (INIS)

    Shirokov, M.I.

    1977-01-01

    Time evolution of unstable states is considered. The usual definition of the decay law is shown to be of a limited application. A more general definition is proposed. The decay law behaviour at long and short times is discussed

  12. Rare beauty and charm decays at LHCb

    CERN Document Server

    INSPIRE-00261996

    2012-01-01

    New results are presented using a data sample with an integrated luminosity of $∼ 1 fb^{−1}$ collected in 2011 with the LHCb detector. The B → $µ^+ µ^−$ and $D^0 → µ^+ µ^−$ results have been presented at a previous conference. The angular distributions and (partial) branching fractions of selected radiative penguin decays are studied using a data sample with an integrated luminosity of ∼ 1$fb^{−1}$ collected in 2011 with the LHCb detector. The partial branching fraction and theoretically clean observables of the decay $B^0 → K^{∗0} µ^+ µ^−$ have been extracted as a function of the dimuon invariant mass. The partial branching fraction of the decay $B^0_s$ → $φµ^+ µ^−$ has also been extracted as a function of the dimuon invariant mass. The branching fraction and first observation of the decay $B^+$ → $π^+ µ^+ µ^−$ is reported. New limits were set on the decay $B → µ^+ µ^− µ^+ µ^−$. Improved limits on the decays $B → µ^+ µ^−$ and $D^0 → µ^+ µ^−$ are...

  13. $\\alpha$-decay study of $^{182,184}$Tl

    CERN Document Server

    Van Beveren, C; Barzakh, A E; Cocolios, T E; de Groote, R P; Fedorov, D; Fedosseev, V N; Ferrer, R; Ghys, L; Huyse, M; Köster, U; Lane, J; Liberati, V; Lynch, K M; Marsh, B A; Molkanov, P L; Procter, T J; Rapisarda, E; Sandhu, K; Seliverstov, M D; Van Duppen, P; Venhart, M; Veselský, M

    2016-01-01

    α -decay spectroscopy of 182,184 Tl has been performed at the CERN isotope separator on-line ( ISOLDE ) facility. New fi ne-structure α decays have been observed for both isotopes. α -decay branching ratios of 0.089 ( 19 ) %, 0.047 ( 6 ) % and 1.22 ( 30 ) % have been deduced for the ( 10 − ) , ( 7 + ) and ( 2 − ) states respectively in 184 Tl and a lower limit of 0.49% for the α -decay branching ratio of 182 Tl. A new half-life of 9.5 ( 2 ) s for the ( 2 − ) state in 184 Tl and 1.9 ( 1 ) s for the low-spin state in 182 Tl has been deduced. Using α – γ coincidence analysis, multiple γ rays were observed de-exciting levels in 178,18 0 Au fed by 182,184 Tl α decays. The γ transitions connecting these low-lying states in 178,18 0 Au are essential to sort the data and possibly identify bands from in- beam studies in these isotopes. Owing to the complex fi ne-structure α decays and limited knowledge about the structure of the daughter nuclei, only partial level schemes could be constructed for bot...

  14. Neutron Decay with PERC: a Progress Report

    International Nuclear Information System (INIS)

    Konrad, G; Abele, H; Erhart, J; Fillunger, H; Gösselsberger, C; Horvath, M; Jericha, E; Klauser, C; Maix, R K; Nowak, S; Sauerzopf, C; Beck, M; Heil, W; Drescher, C; Dubbers, D; Märkisch, B; Mest, H; Rebrova, N; Roick, C; Klenke, J

    2012-01-01

    The PERC collaboration will perform high-precision measurements of angular correlations in neutron beta decay at the beam facility MEPHISTO of the Forschungs-Neutronenquelle Heinz Maier-Leibnitz in Munich, Germany. The new beam station PERC, a clean, bright, and versatile source of neutron decay products, is designed to improve the sensitivity of neutron decay studies by one order of magnitude. The charged decay products are collected by a strong longitudinal magnetic field directly from inside a neutron guide. This combination provides the highest phase space density of decay products. A magnetic mirror serves to perform precise cuts in phase space, reducing related systematic errors. The new instrument PERC is under development by an international collaboration. The physics motivation, sensitivity, and applications of PERC as well as the status of the design and preliminary results on uncertainties in proton spectroscopy are presented in this paper.

  15. Supersymmetry in Z' decays

    International Nuclear Information System (INIS)

    Corcella, G.

    2014-01-01

    I study the phenomenology of new heavy neutral gauge bosons Z', predicted by Grand Unification Theories-driven U(1)' gauge groups and by the sequential standard model. BSM (Beyond Standard Model) decays into supersymmetric final states are accounted for, besides the SM (Standard Model) modes usually investigated. I give an estimate of the number of supersymmetric events in Z' decays possibly expected at LHC, as well as of the product of the Z' cross section times the branching fraction into electron and muon pairs. (author)

  16. $K^{0}_{S}$ production in $\\tau$ decays

    CERN Document Server

    Barate, R; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Nief, J Y; Pietrzyk, B; Boix, G; Casado, M P; Chmeissani, M; Crespo, J M; Delfino, M C; Fernández, E; Fernández-Bosman, M; Garrido, L; Graugès-Pous, E; Juste, A; Martínez, M; Merino, G; Miquel, R; Mir, L M; Park, I C; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Colaleo, A; Creanza, D; De Palma, M; Gelao, G; Iaselli, Giuseppe; Maggi, G; Maggi, M; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Tricomi, A; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Abbaneo, D; Alemany, R; Becker, U; Bright-Thomas, P G; Casper, David William; Cattaneo, M; Cerutti, F; Ciulli, V; Dissertori, G; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Hansen, J B; Harvey, J; Janot, P; Jost, B; Lehraus, Ivan; Mato, P; Minten, Adolf G; Moneta, L; Pacheco, A; Pusztaszeri, J F; Ranjard, F; Rolandi, Luigi; Rousseau, D; Schlatter, W D; Schmitt, M; Schneider, O; Tejessy, W; Teubert, F; Tomalin, I R; Wachsmuth, H W; Wagner, A; Ajaltouni, Ziad J; Badaud, F; Chazelle, G; Deschamps, O; Falvard, A; Ferdi, C; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rosnet, P; Fearnley, Tom; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Rensch, B; Wäänänen, A; Daskalakis, G; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Rougé, A; Rumpf, M; Valassi, Andrea; Verderi, M; Videau, H L; Boccali, T; Focardi, E; Parrini, G; Zachariadou, K; Corden, M; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Lynch, J G; Negus, P; O'Shea, V; Raine, C; Scarr, J M; Smith, K; Teixeira-Dias, P; Thompson, A S; Thomson, E; Thomson, F; Buchmüller, O L; Dhamotharan, S; Geweniger, C; Graefe, G; Hanke, P; Hansper, G; Hepp, V; Kluge, E E; Putzer, A; Sommer, J; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, Peter J; Girone, M; Goodsir, S M; Martin, E B; Marinelli, N; Moutoussi, A; Nash, J; Sedgbeer, J K; Spagnolo, P; Williams, M D; Ghete, V M; Girtler, P; Kneringer, E; Kuhn, D; Rudolph, G; Betteridge, A P; Bowdery, C K; Buck, P G; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Jones, R W L; Williams, M I; Giehl, I; Greene, A M; Hoffmann, C; Jakobs, K; Kleinknecht, K; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Benchouk, C; Bonissent, A; Bujosa, G; Carr, J; Coyle, P; Etienne, F; Leroy, O; Motsch, F; Payre, P; Talby, M; Sadouki, A; Thulasidas, M; Trabelsi, K; Aleppo, M; Antonelli, M; Ragusa, F; Berlich, R; Blum, Walter; Büscher, V; Dietl, H; Ganis, G; Gotzhein, C; Kroha, H; Lütjens, G; Lutz, Gerhard; Mannert, C; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Stenzel, H; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Chen, S; Choi, Y; Cordier, A; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Höcker, A; Jacholkowska, A; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Nikolic, I A; Schune, M H; Tournefier, E; Veillet, J J; Videau, I; Zerwas, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Palla, Fabrizio; Rizzo, G; Sanguinetti, G; Sciabà, A; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Vannini, C; Venturi, A; Verdini, P G; Blair, G A; Bryant, L M; Chambers, J T; Green, M G; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Norton, P R; Thompson, J C; Wright, A E; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Black, S N; Dann, J H; Johnson, R P; Kim, H Y; Konstantinidis, N P; Litke, A M; McNeil, M A; Taylor, G; Booth, C N; Brew, C A J; Cartwright, S L; Combley, F; Kelly, M S; Lehto, M H; Reeve, J; Thompson, L F; Affholderbach, K; Böhrer, A; Brandt, S; Cowan, G D; Grupen, Claus; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Charles, E; Elmer, P; Ferguson, D P S; Gao, Y; González, S; Greening, T C; Hayes, O J; Hu, H; Jin, S; McNamara, P A; Nachtman, J M; Nielsen, J; Orejudos, W; Pan, Y B; Saadi, Y; Scott, I J; Walsh, J; Wu Sau Lan; Wu, X; Yamartino, J M; Zobernig, G

    1998-01-01

    From a sample of about 160k $\\mbox{Z}\\!\\!\\to\\!\\!\\tau^+\\tau^-$ candidates collected with the ALEPH detector at LEP between 1991 and 1995, $\\tau$ lepton decays involving $K^0_S\\!\\to\\!\\pi^+\\pi^-$ are studied. The $K^0_SK^0_L$ associated production in $\\tau$ decays is also investigated. The branching ratios are measured for the inclusive decay $B(\\tau^-\\!\\!\\to\\!\\!K^0_SX^-\

  17. Decay of reverberant sound in a spherical enclosure

    International Nuclear Information System (INIS)

    Carroll, M.M.; Chien, C.F.

    1977-01-01

    The assumption of diffuse reflection (Lambert's Law) leads to integral equations for the wall intensity in a reverberant sound field in the steady state and during decay. The latter equation, in the special case of a spherical enclosure with uniformly absorbent walls and uniform wall intensity, allows exponential decay with a decay time which agrees closely with the Norris--Eyring prediction. The sound-intensity and sound-energy density in the medium, during decay, are also calculated

  18. Rare muon decays and lepton-family number conservation

    International Nuclear Information System (INIS)

    Hoffman, C.M.

    1984-04-01

    A brief historical survey of the discovery of the muon, interest in neutrinoless processes, and lepton-number conservation laws is given. The present view of lepton-number conservation laws and the search for μ → eγ are described. Other experiments are discussed including μ + → e + e + e - decay, μ - Z → e - Z reactions, μ → e γγ decay, other rare muon processes, strangeness-changing muon-number-nonconserving decays, and tau decays. 52 references

  19. Complex beta-decay schemes: Pandemonium lost and paradise regained

    International Nuclear Information System (INIS)

    Firestone, R.B.

    1982-01-01

    The β-decay of 145 Gd has been studied in sufficient detail for comparison with the decay of its fictional analogue Pandemonium. It is shown that > 98% of the 145 Gd decay intensity was observed. This result casts doubt on the value of decay schemes determined solely by statistical techniques. (orig.)

  20. Strangeness in nuclei and neutron stars

    Science.gov (United States)

    Lonardoni, Diego

    2017-01-01

    The presence of exotic particles in the core of neutron stars (NS) has been questioned for a long time. At present, it is still an unsolved problem that drives intense research efforts, both theoretical and experimental. The appearance of strange baryons in the inner regions of a NS, where the density can exceed several times the nuclear saturation density, is likely to happen due to energetic considerations. The onset of strange degrees of freedom is considered as an effective mechanism to soften the equation of state (EoS). This softening affects the entire structure of the star, reducing the pressure and therefore the maximum mass that the star can stably support. The observation of two very massive NS with masses of the order of 2M⊙ seems instead to rule out soft EoS, apparently excluding the possibility of hyperon formation in the core of the star. This inconsistency, usually referred to as the hyperon puzzle, is based on what we currently know about the interaction between strange particles and normal nucleons. The combination of a poor knowledge of the hypernuclear interactions and the difficulty of obtaining clear astrophysical evidence of the presence of hyperons in NS makes the understanding of the behavior of strange degrees of freedom in NS an intriguing theoretical challenge. We give our contribution to the discussion by studying the general problem of the hyperon-nucleon interaction. We attack this issue by employing a quantum Monte Carlo (QMC) technique, that has proven to be successful in the description of strongly correlated Fermion systems, to the study of finite size nuclear systems including strange degrees of freedom, i.e. hypernuclei. We show that many-body hypernuclear forces are fundamental to properly reproduce the ground state physics of Λ hypernuclei from light- to medium-heavy. However, the poor abundance of experimental data on strange nuclei leaves room for a good deal of indetermination in the construction of hypernuclear

  1. Strong intercation corrections to semiweak decays: calculation of the V → Hγ decay rate with αsub(s) accuracy

    International Nuclear Information System (INIS)

    Vysotskij, M.I.

    1980-01-01

    The problem of the search for the Higgs boson in the V → Hγ decay, where V is a vector particle built of anti QQ heavy quark pair is considered. The V → Hγ decay proposed by Wilczek gives possibility to avoid experimental dificulties in detecting Higgs bosons. The probability of this decay and one loop gluan strong corrections to this process have been calculated

  2. Compilations and evaluations of nuclear structure and decay date

    International Nuclear Information System (INIS)

    Lorenz, A.

    The material contained in this compilation is sorted according to eight subject categories: 1. General Compilations; 2. Basic Isotopic Properties; 3. Nuclear Structure Properties; 4. Nuclear Decay Processes: Half-lives, Energies and Spectra; 5. Nuclear Decay Processes: Gamma-rays; 6. Nuclear Decay Processes: Fission Products; 7. Nuclear Decay Processes: (Others); 8. Atomic Processes

  3. Search for Nucleon Decays in Super-Kamiokande

    International Nuclear Information System (INIS)

    Miura, Makoto

    2010-01-01

    Grand Unified Theories (GUTs) is motivated by merging of the coupling constants of the strong, weak, and electromagnetic forces at a large energy scale (∼10 16 GeV), which is out of the reach of accelerators. One of the other general features of GUTs is that they allow lepton and baryon number violations and they predict instability of nucleons. Then nucleon decay experiments are the direct probe for GUTs. The Super-Kamiokande (SK) is a water Cherenkov detector which keeps running to detect nucleon decays with large mass. There are no other nucleon decay detectors which have as long exposure as SK. The results of nucleon decay search based on 173 kton year (1996-2008) will be presented in the conference.The favored decay mode in GUTs based on SU(5) symmetry is p→e + π 0 . On the other hand, p→ν K + is favored by SUSY GUTs model. Those two modes will be mainly discussed. (authors)

  4. A combined treatment of neutrino decay and neutrino oscillations

    International Nuclear Information System (INIS)

    Lindner, Manfred; Ohlsson, Tommy; Winter, Walter

    2001-01-01

    Neutrino decay in vacuum has often been considered as an alternative to neutrino oscillations. Because nonzero neutrino masses imply the possibility of both neutrino decay and neutrino oscillations, we present a model-independent formal treatment of these combined scenarios. For that, we show for the example of Majoron decay that in many cases decay products are observable and may even oscillate. Furthermore, we construct a minimal scenario in which we study the physical implications of neutrino oscillations with intermediate decays

  5. Decay of 99Mo

    International Nuclear Information System (INIS)

    Dickens, J.K.; Love, T.A.

    1976-01-01

    Relative intensities for K x-rays and gamma rays emanating from 99 Mo in equilibrium with its 99 Tc* daughter have been measured using several Ge photon detectors. Combining these intensities with an evaluated set of electron-conversion coefficients has provided a set of absolute intensities for the observed gamma rays. The absolute intensity for the dominant 140.5-keV gamma ray in 99 Tc was determined to be 90.7 +- 0.6/100 99 Mo disintegrations for 99 Mo decay in equilibrium with decay of the 99 Tc* daughter

  6. A phenomenological analysis of non-resonant charm meson decays

    Energy Technology Data Exchange (ETDEWEB)

    Bediaga, I.; Goebel, C. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Mendez-Galain, R. [Montevideo Univ. (Uruguay). Facultad de Ingenieria

    1997-07-01

    We analyse the consequences of the usual assumption of a constant function to fit non-resonant decays from experimental Dalitz plot describing charmed meson decays. We first show, using the D{sup +} -> K{sup 0} {pi}{sup +} {pi}{sup 0} decay channel as an example, how an inadequate extraction of the non-resonant contribution could yield incorrect measurements for the resonant channels. We analyse how the correct study of this decay will provide a test for the validity of factorization in D meson decays. Finally, we show how form factors that can be measured from the D{sup +}{sub s} -> {pi}{sup -} {pi}{sup +} {pi}{sup +} decay. We emphasize its relevance for the study of the decay {tau} -> v{sub t} 3{pi} and the extraction of the {alpha}{sub 1} meson width. (author) 26 refs., 6 figs.

  7. Production and decay of the τ lepton

    International Nuclear Information System (INIS)

    Scholz, S.

    1990-02-01

    With the CELLO detector at the storage ring PETRA at a c.m. energy of √s=35 GeV production and decay of the τ lepton were studied. For the production of τ pairs in the e - e + -annihilation the cross section and the charge asymmetry were measured. For the decay of the τ lepton for the first time all exclusive and the topological branching ratios were measured simultaneously. Most of the measured exclusive branching ratios were determined with the highest hitherto reached precision of a single measurement and agree generally well with the hitherto world mean values. For the decays τ - →e - anti ν e ν τ , τ - →π - π 0 π 0 ν τ and τ - →π - π + π - ν τ however branching ratios were measured, which lie 1-2 standard deviations above the world mean values. The measurement of the topological branching ratios BR 1 respectively BR 3 yielded by 2 standard deviations lower respectively higher values than the world average. While the sum of all exclusive branching ratios from the hitherto measurements exhibit a deficit of ≅6% missing decays, the results of this measurement sum up to 99.3% and let therefore few space for unknown decay modes of the τ lepton. Contrarily to the world mean values especially the topological 1-prong branching ratio agrees with the sum of the exclusive decay rates. The branching ratio into decays, which are not predicted by the standard model, could by intensive systematic studies on the completeness of the analyzed τ event set and by the directed search for such decays be given with smaller than 1% (95% c.l.). (orig./HSI) [de

  8. Beta decay of 22O

    International Nuclear Information System (INIS)

    Hubert, F.; Dufour, J.P.; Moral, R. Del; Fleury, A.; Jean, D.; Pravikoff, M.S.; Geissel, H.; Schmidt, K.H.; Hanelt, E.

    1991-01-01

    22 O nuclei were produced as fragments of a 60 MeV/n 40 Ar beam interacting with a thick Be target. They were selected from all the produced nuclei with the LISE separator. γ spectra in coincidence with the β decay were measured. Partial decay scheme of 22 O is given. Similarities between experiments and calculations are discussed. (G.P.) 10 refs.; 3 figs

  9. Parametric decay of the curvaton

    International Nuclear Information System (INIS)

    Enqvist, K; Nurmi, S; Rigopoulos, G I

    2008-01-01

    We argue that the curvaton decay takes place most naturally by way of a broad parametric resonance. The mechanism is analogous to resonant inflaton decay but does not require any tuning of the curvaton coupling strength to other scalar fields. For low scale inflation and a correspondingly low mass scale for the curvaton, we speculate on observable consequences including the possibility of stochastic gravitational waves

  10. Double Charge Exchange Reactions and Double Beta Decay

    Science.gov (United States)

    Auerbach, N.

    2018-05-01

    The subject of this presentation is at the forefront of nuclear physics, namely double beta decay. In particular one is most interested in the neutrinoless process of double beta decay, when the decay proceeds without the emission of two neutrinos. The observation of such decay would mean that the lepton conservation symmetry is violated and that the neutrinos are of Majorana type, meaning that they are their own anti-particles. The life time of this process has two unknowns, the mass of the neutrino and the nuclear matrix element. Determining the nuclear matrix element and knowing the cross-section well will set limits on the neutrino mass. There is a concentrated effort among the nuclear physics community to calculate this matrix element. Usually these matrix elements are a very small part of the total strength of the transition operators involved in the process. There is no simple way to “calibrate” the nuclear double beta decay matrix element. The double beta decay is a double charge exchange process, therefore it is proposed that double charge exchange reactions using ion projectiles on nuclei that are candidates for double beta decay, will provide additional necessary information about the nuclear matrix elements.

  11. Decay of Solar Wind Turbulence behind Interplanetary Shocks

    Energy Technology Data Exchange (ETDEWEB)

    Pitňa, Alexander; Šafránková, Jana; Němeček, Zdeněk [Charles University, Faculty of Mathematics and Physics, V Holesovickach 2, Prague, CZ-18000 (Czech Republic); Franci, Luca, E-mail: offelius@gmail.com [Dipartimento di Fisica e Astronomia, Universita degli Studi di Firenze, I-50125 Firenze (Italy)

    2017-07-20

    We investigate the decay of magnetic and kinetic energies behind IP shocks with motivation to find a relaxation time when downstream turbulence reaches a usual solar wind value. We start with a case study that introduces computation techniques and quantifies a contribution of kinetic fluctuations to the general energy balance. This part of the study is based on high-time (31 ms) resolution plasma data provided by the Spektr-R spacecraft. On the other hand, a statistical part is based on 92 s Wind plasma and magnetic data and its results confirm theoretically established decay laws for kinetic and magnetic energies. We observe the power-law behavior of the energy decay profiles and we estimated the power-law exponents of both kinetic and magnetic energy decay rates as −1.2. We found that the decay of MHD turbulence does not start immediately after the IP shock ramp and we suggest that the proper decay of turbulence begins when a contribution of the kinetic processes becomes negligible. We support this suggestion with a detailed analysis of the decay of turbulence at the kinetic scale.

  12. Decay of Solar Wind Turbulence behind Interplanetary Shocks

    International Nuclear Information System (INIS)

    Pitňa, Alexander; Šafránková, Jana; Němeček, Zdeněk; Franci, Luca

    2017-01-01

    We investigate the decay of magnetic and kinetic energies behind IP shocks with motivation to find a relaxation time when downstream turbulence reaches a usual solar wind value. We start with a case study that introduces computation techniques and quantifies a contribution of kinetic fluctuations to the general energy balance. This part of the study is based on high-time (31 ms) resolution plasma data provided by the Spektr-R spacecraft. On the other hand, a statistical part is based on 92 s Wind plasma and magnetic data and its results confirm theoretically established decay laws for kinetic and magnetic energies. We observe the power-law behavior of the energy decay profiles and we estimated the power-law exponents of both kinetic and magnetic energy decay rates as −1.2. We found that the decay of MHD turbulence does not start immediately after the IP shock ramp and we suggest that the proper decay of turbulence begins when a contribution of the kinetic processes becomes negligible. We support this suggestion with a detailed analysis of the decay of turbulence at the kinetic scale.

  13. Alpha decay and various problems related to it

    International Nuclear Information System (INIS)

    Katori, Kenji

    1992-01-01

    On the proton-excessive nucleus side of lanthanide and actinide, alpha decay is the main decay mode. In lanthanide region, alpha decay has been measured to the drip line for most even-even nuclei. In the measurement of alpha decay, emitted energy and life are measured, but the measurement of converted alpha width remains in the limited range. In order to obtain the converted alpha width of high accuracy, the nucleus formation in larger quantity on the drip line and the simultaneous measurement with a multiple detector system including gamma ray and beta ray are required. In this paper, three topics related to alpha cluster and alpha decay and the problems that confront at present are discussed. The continuation to exist of alpha cluster structure to heavy nuclei, the analysis of lanthanide nucleus region by the alpha giant resonance model, and the new data on the alpha ray decaying from the mass of 175, 176 and 177 are reported. In lanthanide nucleus region, remarkable interference was not observed between beta-2 and beta-3 modes in the converted alpha width measured between the ground states. The present problems in alpha decay are enumerated. (K.I.)

  14. Limits on Tensor Coupling from Neutron $\\beta$-Decay

    OpenAIRE

    Pattie Jr, Robert W.; Hickerson, Kevin P.; Young, Albert R.

    2013-01-01

    Limits on the tensor couplings generating a Fierz interference term, b, in mixed Gamow-Teller Fermi decays can be derived by combining data from measurements of angular correlation parameters in neutron decay, the neutron lifetime, and $G_{\\text{V}}=G_{\\text{F}} V_{ud}$ as extracted from measurements of the $\\mathcal{F}t$ values from the $0^{+} \\to 0^{+}$ superallowed decays dataset. These limits are derived by comparing the neutron $\\beta$-decay rate as predicted in the standard model with t...

  15. Double γ decay in 90Zr

    International Nuclear Information System (INIS)

    Mucciolo, E.R.

    1988-01-01

    The double γ decay between θ + n - θ + i of 90 Zr was observed. The θ + n level was fed through the decay of 90 Sr. The experimental arrangement consisted of a double coincidence system between the two semiconductor detectors. (A.C.A.S.) [pt

  16. Assessment of rock mass decay in artificial slopes

    NARCIS (Netherlands)

    Huisman, M.

    2006-01-01

    This research investigates the decay of rock masses underlying slopes, and seeks to quantify the relations of such decay with time and geotechnical parameters of the slope and rock mass. Decay can greatly affect the geotechnical properties of rocks within engineering timescales, and may induce a

  17. Single isospin decay amplitude and CP violation

    Energy Technology Data Exchange (ETDEWEB)

    Deshpande, N.G. [Oregon Univ., Eugene, OR (United States). Inst. of Theoretical Science; He, Xiaogang [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Pakvasa, S. [Hawaii Univ., Honolulu, HI (United States). Dept. of Physics and Astronomy

    1996-06-01

    While for K meson or hyperon decays, the partial rate asymmetries are always zero if the final states are single isospin states, in B decays the situation is dramatically different and partial rate asymmetries can be non-zero if the final states are single isospin states. Partial rate asymmetries were calculated for several B decays with single isospin amplitude in the finale states using factorization approximation. It was found that more intermediate on-shell states with different Cabbibbo-Kobayashi-Maskawa factors are allowed in B decay and CP violating partial rate asymmetries need not to be zero even if the final state contains only a single isospin state. 17 refs., 4 figs.

  18. Search for radiative B meson decays

    International Nuclear Information System (INIS)

    Lesiak, T.; Muryn, B.; Nowak, G.; Antreasyan, D.; Irion, J.; McBride, P.; Strauch, K.; Bartels, H.W.; Bienlein, J.K.; Brockmueller, K.; Jakubowski, Z.; Karch, K.; Kloiber, T.; Koch, W.; Maschmann, W.; Meyer, H.; Skwarnicki, T.; Trost, H.J.; Voigt, A.; Wachs, K.; Zschorsch, P.; Besset, D.; Cabenda, R.; Cowan, R.; Bieler, C.; Graaf, K.; Heinsius, F.H.; Kiel, T.; Krueger, S.; Lekebusch, R.; Nernst, R.; Sievers, D.; Stock, V.; Strohbusch, U.; Bloom, E.D.; Clare, R.; Cooper, S.; Fairfield, K.; Fridman, A.; Gaiser, J.; Gelphman, D.; Godfrey, G.; Hofstadter, R.; Kirkbride, I.; Lee, R.; Leffler, S.; Litke, A.M.; Lockman, W.; Lowe, S.; Niczyporuk, B.; Pollock, B.; Schwarz, A.; Tompkins, J.; Van Uitert, B.; Wacker, K.; Brock, I.; Engler, A.; Kraemer, R.W.; Marlow, D.; Messing, F.; Prindle, D.; Renger, B.; Rippich, C.; Vogel, H.; Cavalli-Sforza, M.; Coyne, D.; Folger, G.; Glaser, G.; Kobel, M.; Lurz, B.; Schuette, J.; Volland, U.; Wegener, H.; Janssen, H.; Koenig, A.C.; Metzger, W.J.; Reidenbach, M.; Schotanus, J.; Walle, R.T. van de; Walk, W.; Keh, S.; Kilian, H.; Koenigsmann, K.; Scheer, M.; Schmitt, P.; Marsiske, H.; Williams, D.A.

    1992-01-01

    The Crystal Ball detector at the e + e - storage ring DORIS-II has been used to search for radiative B meson decays, especially of the type b→sγ. No mono-energetic γ-lines have been found in the inclusive photon spectrum from Υ(4S) decays, and upper limits are obtained for radiative decays of B mesons to various strange mesons and to the D*. Integrating the photon spectrum over the corresponding energy range, we find BR(B→γX) -3 , at 90% confidence level for the mass range 892 MeV≤M X ≤2045 MeV. (orig.)

  19. Rare kaon, muon, and pion decay

    International Nuclear Information System (INIS)

    Littenberg, L.

    1998-01-01

    The author discusses the status of and prospects for the study of rare decays of kaons, muons, and pions. Studies of rare kaon decays are entering an interesting new phase wherein they can deliver important short-distance information. It should be possible to construct an alternative unitarity triangle to that determined in the B sector, and thus perform a critical check of the Standard Model by comparing the two. Rare muon decays are beginning to constrain supersymmetric models in a significant way, and future experiments should reach sensitivities which this kind of model must show effects, or become far less appealing

  20. Structure of β-decay strength functions

    International Nuclear Information System (INIS)

    Naumov, Y.V.; Bykov, A.A.; Izosimov, I.N.

    1983-01-01

    The experimental and theoretical studies on the structure of the Gamow--Teller β-decay strength functions are reviewed. Also considered are processes such as M1 γ decay of analog states, the emission of delayed protons, neutrons, and α particles, delayed fission, and the (p, n) reaction at proton energies 100--200 MeV. The results of measurements of the strength functions by γ-ray total absorption are analyzed. It is shown that the β + decay of nuclei far from the stability band exhibits a new type of collective charge-exchange excitation: Gamow--Teller resonance with μ/sub tau/ = +1

  1. Nonresonant decay of lower hybrid waves

    International Nuclear Information System (INIS)

    Brambilla, M.; Liberman, B.; Pesic, S.S.; Moreau, D.

    1979-01-01

    Parametric decay of Lower Hybrid waves has been extensively studied since a few years. To derive the dispersion relation of the decay waves, two different approaches have been used in the literature. In the first the pump electric field is assumed to be homogeneous in space (dipole approximation) and Vlasov Equation is integrated in the Oscillating Center Coordinates (OCC). In the second approach the parametric decay process is considered as the linear stage of a three wave interaction (pump, sideband and beat wave) and the dispersion relation is obtained from a recursive solution of Vlasov equation

  2. Search for radiative B meson decays

    International Nuclear Information System (INIS)

    Lesiak, T.; Muryn, B.; Nowak, G.; Antreasyan, D.; Irion, J.; McBride, P.; Strauch, K.; Bartels, H.W.; Bienlein, J.K.; Brockmueller, K.; Jakubowski, Z.; Karch, K.; Kloiber, T.; Koch, W.; Maschmann, W.; Meyer, H.; Skwarnicki, T.; Trost, H.J.; Voigt, A.; Wachs, K.; Zschorsch, P.; Besset, D.; Cabenda, R.; Cowan, R.; Bieler, C.; Graaf, K.; Heinsius, F.H.; Kiel, T.; Krueger, S.; Lekebusch, R.; Nernst, R.; Sievers, D.; Stock, V.; Strohbusch, U.; Bloom, E.D.; Clare, R.; Cooper, S.; Fairfield, K.; Fridman, A.; Gaiser, J.; Gelphman, D.; Godfrey, G.; Hofstadter, R.; Kirkbride, I.; Lee, R.; Leffler, S.; Litke, A.M.; Lockman, W.; Lowe, S.; Niczyporuk, B.; Pollock, B.; Schwarz, A.; Tompkins, J.; Van Uitert, B.; Wacker, K.; Brock, I.; Engler, A.; Kraemer, R.W.; Marlow, D.; Messing, F.; Prindle, D.; Renger, B.; Rippich, C.; Vogel, H.; Cavalli-Sforza, M.; Coyne, D.; Folger, G.; Glaser, G.; Kobel, M.; Lurz, B.; Schuette, J.; Volland, U.; Wegener, H.; Janssen, H.; Koenig, A.C.; Metzger, W.J.; Reidenbach, M.; Schotanus, J.; Walle, R.T. van de; Walk, W.; Keh, S.; Kilian, H.; Koenigsmann, K.; Scheer, M.; Schmitt, P.; Marsiske, H.; Peck, C.; Porter, F.C.; Ratoff, P.; Williams, D.A.

    1991-07-01

    The Crystal Ball detector at the ε + ε - storage ring DORIS-II has been used to search for radiative B meson decays, especially of the type b→sγ. No mono-energetic γ-lines have been found in the inclusive photon spectrum from Υ(4S) decays, and upper limits are obtained for radiative decays of B mesons to various strange mesons and to the D*. Integrating the photon spectrum over the corresponding energy range, we find BR(B→γX) -3 at 90% confidence level for the mass range 892 MeV≤M X ≤2045 MeV. (orig.)

  3. Studies of Excited $D$ mesons in $B$ meson decays

    CERN Document Server

    AUTHOR|(CDS)2082679

    This thesis documents the studies of several three-body B + meson decays, each with a charged charmed meson in the final state. All analyses presented use a data sample recorded by the LHCb detector in 2011 and 2012, corresponding to an integrated luminosity of 3.0 $fb^{-1}$ of $pp$ collision data. The $B^{+} \\to D^{-}K^{+}\\pi^{+}$ and $B^{+} \\to D^{+}K^{+}\\pi^{-}$ decay modes are observed for the first time. The branching fraction of the favoured $B^{+} \\to D^{-}K^{+}\\pi^{+}$ decay mode is measured relative to the topologically similar $B^{+} \\to D^{-}\\pi^{+}\\pi^{+}$ decay and the $B^{+} \\to D^{-}K^{+}\\pi^{+}$ final state is used as a normalisation channel for the suppressed $B^{+} \\to D^{+}K^{+}\\pi^{-}$ decay branching fraction measurement. Searches are performed for the quasi-two-body decays $B^{+} \\to D^{+}K^{*}(892)^{0}$ and $B^{+} \\to D_{2}^{*}(2460)^{0}K^{+}$, using the sample of $B^{+} \\to D^{+}K^{+}\\pi^{-}$ candidate decays. No significant signals are observed for either decay mode and upper limits a...

  4. Beta decay of 31,32Na and 31Mg

    International Nuclear Information System (INIS)

    Klotz, G.; Baumann, P.; Bounajma, M.; Huck, A.; Knipper, A.; Walter, G.; Poves, A.; Retamosa, J.

    1993-01-01

    31,32 Na and 31 Mg beta decays were studied at the CERN on-line mass separator ISOLDE by gamma, gamma-gamma and neutron-gamma measurements. In the 31 Na decay, the assignment of previously reported γ transitions and the observation of a new level at 3760 keV lead to a revised decay scheme. In the 31 Mg → 31 Al decay, a new decay scheme involves ten β branches and three states are reported for the first time. New spectroscopic results have been obtained in the 32 Na β - decay. A previously non-interpreted 1436 keV γ ray is now assigned in the 32 Mg scheme. (author) 33 refs., 16 figs., 12 tabs

  5. Heavy quark spectroscopy and decay

    International Nuclear Information System (INIS)

    Schindler, R.H.

    1987-01-01

    The understanding of q anti q systems containing heavy, charmed, and bottom quarks has progressed rapidly in recent years, through steady improvements in experimental techniques for production and detection of their decays. These lectures are meant to be an experimentalist's review of the subject. In the first of two lectures, the existing data on the spectroscopy of the bound c anti c and b anti b systems will be discussed. Emphasis is placed on comparisons with the theoretical models. The second lecture covers the rapidly changing subject of the decays of heavy mesons (c anti q and b anti q), and their excited states. In combination, the spectroscopy and decays of heavy quarks are shown to provide interesting insights into both the strong and electroweak interactions of the heavy quarks. 103 refs., 39 figs

  6. Energy Distributions from Three-Body Decaying Many-Body Resonances

    International Nuclear Information System (INIS)

    Alvarez-Rodriguez, R.; Jensen, A. S.; Fedorov, D. V.; Fynbo, H. O. U.; Garrido, E.

    2007-01-01

    We compute energy distributions of three particles emerging from decaying many-body resonances. We reproduce the measured energy distributions from decays of two archetypal states chosen as the lowest 0 + and 1 + resonances in 12 C populated in β decays. These states are dominated by sequential, through the 8 Be ground state, and direct decays, respectively. These decay mechanisms are reflected in the ''dynamic'' evolution from small, cluster or shell-model states, to large distances, where the coordinate or momentum space continuum wave functions are accurately computed

  7. Compilations and evaluations of nuclear structure and decay data

    International Nuclear Information System (INIS)

    Lorenz, A.

    1978-10-01

    This is the fourth issue of a report series on published and to-be-published compilations and evaluations of nuclear structure and decay (NSD) data. This compilation is published and distributed by the IAEA Nuclear Data Section every year. The material contained in this compilation is sorted according to eight subject categories: General compilations; basic isotopic properties; nuclear structure properties; nuclear decay processes, half-lives, energies and spectra; nuclear decay processes, gamma-rays; nuclear decay processes, fission products; nuclear decay processes (others); atomic processes

  8. Production of $\\Sigma^{0}$ and $\\Omega^{-}$ in Z decays

    CERN Document Server

    Adam, W; Agasi, E; Ajinenko, I; Aleksan, Roy; Alekseev, G D; Alemany, R; Allport, P P; Almehed, S; Amaldi, Ugo; Amato, S; Andreazza, A; Andrieux, M L; Antilogus, P; Apel, W D; Arnoud, Y; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barate, R; Barbi, M S; Bardin, Dimitri Yuri; Baroncelli, A; Bärring, O; Barrio, J A; Bartl, Walter; Bates, M J; Battaglia, Marco; Baubillier, M; Baudot, J; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Belous, K S; Benvenuti, Alberto C; Berggren, M; Bertrand, D; Bianchi, F; Bigi, M; Bilenky, S M; Billoir, P; Bloch, D; Blume, M; Blyth, S; Bolognese, T; Bonesini, M; Bonivento, W; Booth, P S L; Borisov, G; Bosio, C; Bosworth, S; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Bozzo, M; Branchini, P; Brand, K D; Brenke, T; Brenner, R A; Bricman, C; Brillault, L; Brown, R C A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschmann, P; Buys, A; Cabrera, S; Caccia, M; Calvi, M; Camacho-Rozas, A J; Camporesi, T; Canale, V; Canepa, M; Cankocak, K; Cao, F; Carena, F; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Cerrito, L; Chabaud, V; Chapkin, M M; Charpentier, P; Chaussard, L; Chauveau, J; Checchia, P; Chelkov, G A; Chen, M; Chierici, R; Chliapnikov, P V; Chochula, P; Chorowicz, V; Chudoba, J; Cindro, V; Collins, P; Contreras, J L; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Crawley, H B; Crennell, D J; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Dahl-Jensen, Erik; Dahm, J; D'Almagne, B; Dam, M; Damgaard, G; Dauncey, P D; Davenport, Martyn; Da Silva, W; Defoix, C; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Brabandere, S; De Clercq, C; La Vaissière, C de; De Lotto, B; De Min, A; De Paula, L S; De Saint-Jean, C; Dijkstra, H; Di Ciaccio, Lucia; Djama, F; Dolbeau, J; Dönszelmann, M; Doroba, K; Dracos, M; Drees, J; Drees, K A; Dris, M; Dufour, Y; Edsall, D M; Ehret, R; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Elsing, M; Engel, J P; Ershaidat, N; Erzen, B; Espirito-Santo, M C; Falk, E; Fassouliotis, D; Feindt, Michael; Ferrer, A; Filippas-Tassos, A; Firestone, A; Fischer, P A; Föth, H; Fokitis, E; Fontanelli, F; Formenti, F; Franek, B J; Frenkiel, P; Fries, D E C; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gandelman, M; García, C; García, J; Gaspar, C; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Gerber, J P; Gerdyukov, L N; Gibbs, M; Gokieli, R; Golob, B; Gopal, Gian P; Gorn, L; Górski, M; Guz, Yu; Gracco, Valerio; Graziani, E; Grosdidier, G; Grzelak, K; Gumenyuk, S A; Gunnarsson, P; Günther, M; Guy, J; Hahn, F; Hahn, S; Hallgren, A; Hamacher, K; Hao, W; Harris, F J; Hedberg, V; Henriques, R P; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Higón, E; Hilke, Hans Jürgen; Hill, T S; Holmgren, S O; Holt, P J; Holthuizen, D J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, L B; Jönsson, P E; Joram, Christian; Juillot, P; Kaiser, M; Kapusta, F; Karafasoulis, K; Karlsson, M; Karvelas, E; Katsanevas, S; Katsoufis, E C; Keränen, R; Khomenko, B A; Khovanskii, N N; King, B J; Kjaer, N J; Klein, H; Klovning, A; Kluit, P M; Köne, B; Kokkinias, P; Koratzinos, M; Korcyl, K; Kostyukhin, V; Kourkoumelis, C; Kuznetsov, O; Kramer, P H; Krammer, Manfred; Kreuter, C; Kronkvist, I J; Krumshtein, Z; Krupinski, W; Kubinec, P; Kucewicz, W; Kurvinen, K L; Lacasta, C; Laktineh, I; Lamblot, S; Lamsa, J; Lanceri, L; Lane, D W; Langefeld, P; Last, I; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Legan, C K; Leitner, R; Lemoigne, Y; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Liko, D; Lindner, R; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J N; Maehlum, G; Maio, A; Malychev, V; Mandl, F; Marco, J; Marco, R P; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Maron, T; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Masik, J; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; Medbo, J; Merk, M; Meroni, C; Meyer, S; Meyer, W T; Michelotto, M; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Møller, R; Mönig, K; Monge, M R; Morettini, P; Müller, H; Mundim, L M; Murray, W J; Muryn, B; Myatt, Gerald; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Neumann, W; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nieuwenhuizen, M; Nikolaenko, V; Niss, P; Nomerotski, A; Normand, Ainsley; Oberschulte-Beckmann, W; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Österberg, K; Ouraou, A; Paganini, P; Paganoni, M; Pagès, P; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Passeri, A; Pegoraro, M; Peralta, L; Pernegger, H; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Petrovykh, M; Phillips, H T; Piana, G; Pierre, F; Pimenta, M; Pindo, M; Plaszczynski, S; Podobrin, O; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Prest, M; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Rames, J; Ratoff, P N; Read, A L; Reale, M; Rebecchi, P; Redaelli, N G; Reid, D; Renton, P B; Resvanis, L K; Richard, F; Richardson, J; Rídky, J; Rinaudo, G; Ripp, I; Romero, A; Roncagliolo, I; Ronchese, P; Roos, L; Rosenberg, E I; Rosso, E; Roudeau, Patrick; Rovelli, T; Rückstuhl, W; Ruhlmann-Kleider, V; Ruiz, A; Rybicki, K; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sánchez, J; Sannino, M; Schimmelpfennig, M; Schneider, H; Schwickerath, U; Schyns, M A E; Sciolla, G; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Seitz, A; Sekulin, R L; Shellard, R C; Siccama, I; Siegrist, P; Simonetti, S; Simonetto, F; Sissakian, A N; Sitár, B; Skaali, T B; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Solovyanov, O; Sosnowski, R; Souza-Santos, D; Spassoff, Tz; Spiriti, E; Sponholz, P; Squarcia, S; Stanescu, C; Stapnes, Steinar; Stavitski, I; Stichelbaut, F; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Tavernet, J P; Chikilev, O G; Tilquin, A; Timmermans, J; Tkatchev, L G; Todorov, T; Toet, D Z; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Trischuk, W; Tristram, G; Trombini, A; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tyndel, M; Tzamarias, S; Überschär, B; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; Van der Velde, C; van Apeldoorn, G W; van Dam, P; Van Doninck, W K; Van Eldik, J; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Vilanova, D; Vincent, P; Vitale, L; Vlasov, E; Vodopyanov, A S; Vrba, V; Wahlen, H; Walck, C; Waldner, F; Weierstall, M; Weilhammer, Peter; Weiser, C; Wetherell, Alan M; Wicke, D; Wickens, J H; Wielers, M; Wilkinson, G R; Williams, W S C; Winter, M; Woschnagg, K; Yip, K; Yushchenko, O P; Zach, F; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zito, M; Zontar, D; Zuberi, R; Zucchelli, G C; Zumerle, G

    1996-01-01

    Reconstructed \\lam\\ baryon decays and photon conversions in DELPHI are used to measure the \\sig\\ production rate from hadronic Z^0 decays at LEP. The number of \\sig\\ decays per hadronic Z decay is found to be: \\begin{center} = \\wffe{0.070}{0.010}{0.010 }{}. \\end{center} \\bigskip The \\Omega^- production rate is similarly measured to be: \\begin{center} = \\wffe{0.0014}{0.0002}{0.0004}{} \\end{center} by a combination of methods using constrained fits to the whole decay chain and particle identification.

  9. Context-dependent decay of motor memories during skill acquisition.

    Science.gov (United States)

    Ingram, James N; Flanagan, J Randall; Wolpert, Daniel M

    2013-06-17

    Current models of motor learning posit that skill acquisition involves both the formation and decay of multiple motor memories that can be engaged in different contexts. Memory formation is assumed to be context dependent, so that errors most strongly update motor memories associated with the current context. In contrast, memory decay is assumed to be context independent, so that movement in any context leads to uniform decay across all contexts. We demonstrate that for both object manipulation and force-field adaptation, contrary to previous models, memory decay is highly context dependent. We show that the decay of memory associated with a given context is greatest for movements made in that context, with more distant contexts showing markedly reduced decay. Thus, both memory formation and decay are strongest for the current context. We propose that this apparently paradoxical organization provides a mechanism for optimizing performance. While memory decay tends to reduce force output, memory formation can correct for any errors that arise, allowing the motor system to regulate force output so as to both minimize errors and avoid unnecessary energy expenditure. The motor commands for any given context thus result from a balance between memory formation and decay, while memories for other contexts are preserved. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Theory of two-step two-proton decays of nuclei

    International Nuclear Information System (INIS)

    Kadmensky, S. G.; Ivankov, Yu. V.

    2014-01-01

    A general theory of many-body diagonal and nondiagonal one-proton decays of spherical and deformed nuclei is developed on the basis of an approach not employing R-matrix theory in describing deep-subbarrier alpha and one-proton decays of nuclei but relying on integral formulas for the widths with respect to these decays. With the aid of this theory and by means of a diagram technique, a formalism is developed for describing two-step two-proton decays of a (Z, A) parent nucleus, which proceed as two successive time-separated one-proton decays of the parent and intermediate [(Z − 1, A − 1)] nuclei, these decays being related by the Green’s function for the intermediate nucleus, G(Z − 1, A − 1). It is shown that, upon taking into account, in this Green’s function, intermediate-nucleus states that are on- and off-shell states for the decaying system, there arise, respectively, sequential and virtual two-proton decays of parent nuclei. Expressions for the widths with respect to sequential and virtual two-proton decays from the ground and excited states of spherical and deformed nuclei and for the angular and energy distributions of emitted protons are obtained

  11. Two-photon decay in heavy atoms and ions

    International Nuclear Information System (INIS)

    Mokler, P.H.; Dunford, R.W

    2003-08-01

    We review the status of and comment on current developments in the field of two-photon decay in atomic physics research. Recent work has focused on two-photon decays in highly-charged ions and two-photon decay of inner-shell vacancies in heavy neutral atoms. We emphasize the importance of measuring the shape of the continuum emission in two-photon decay as a probe of relativistic effects in the strong central fields found in heavy atomic systems. New experimental approaches and their consequences will be discussed. (orig.)

  12. Calculated secondary yields for proton broadband using DECAY TURTLE

    International Nuclear Information System (INIS)

    Sondgeroth, A.

    1995-02-01

    The calculations for the yields were done by Al Sondgeroth and Anthony Malensek. The authors used the DECAY deck called PBSEC E.DAT from the CMS DECKS library. After obtaining the run modes and calibration modes from the liaison physicist, they made individual decay runs, using DECAY TURTLE from the CMS libraries and a production spectrum subroutine which was modified by Anthony, for each particle and decay mode for all particle types coming out of the target box. Results were weighted according to branching ratios for particles with more than one decay mode. The production spectra were produced assuming beryllium as the target. The optional deuterium target available to broadband will produce slightly higher yields. It should be noted that they did not include pion yields from klong decays because they could not simulate three body decays. Pions from klongs would add a very small fraction to the total yield

  13. Alpha-decay chains of superheavy nuclei 292-296118

    Science.gov (United States)

    Singh, U. K.; Kumawat, M.; Saxena, G.; Kaushik, M.; Jain, S. K.

    2018-05-01

    We have employed relativistic mean-field plus BCS (RMF+BCS) approach for the study of even-even superheavy nuclei with Z = 118 which is the last and recent observed element in the periodic chart so far. Our study includes binding energies, Qα values, alpha-decay half-lives and spontaneous decay half-lives along with comparison of available experimental data and the results of FRDM calculations. We find an excellent match with the only known decay chain of 294118 for Z = 118 so far and predict decay chain of 292118 and 296118 in consistency with known experimental decay chains and FRDM results. These results may provide a very helpful insight to conduct experiments for realizing the presence of nuclei with Z = 118.

  14. Crystal Ball results on tau decays

    International Nuclear Information System (INIS)

    Lowe, S.T.

    1987-10-01

    This report reviews measurements and upper limit determinations for a number of exclusive 1-prong tau decay modes using the Crystal Ball detector. These results are important input to the apparent discrepancy between the topological and sum-of-exclusive branching fractions in 1-prong tau decays

  15. Hadronic decay puzzle in charmonium physics

    International Nuclear Information System (INIS)

    Gu Yifan

    1996-01-01

    Recent experimental results obtained at Beijing Electron-proton Collider sensitivity level the crisply defined nature of the hadronic decay puzzle in charmonium physics. Discovery of new anomalous decay modes breaks with the previously established pattern of the puzzle, and poses new challenges for its theoretical understanding

  16. Rare Z decays and neutrino flavor universality

    Energy Technology Data Exchange (ETDEWEB)

    Durieux, Gauthier [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Cornell Univ. Ithaca, NY (United States). Lab. for Elementary Particle Physics; Univ. Catholique de Louvain, Louvain-la-Neuve (Belgium). Centre for Cosmology, Particle Physics and Phenomenology; Grossman, Yuval; Kuflik, Erik [Cornell Univ. Ithaca, NY (United States). Lab. for Elementary Particle Physics; Koenig, Matthias [Mainz Univ. (Germany). PRISMA Cluster of Excellence; Mainz Univ. (Germany). Mainz Inst. for Theoretical Physics; Ray, Shamayita [Cornell Univ. Ithaca, NY (United States). Lab. for Elementary Particle Physics; Calcutta Univ. (India). Dept. of Physics

    2015-12-15

    We study rare four-body decays of the Z-boson involving at least one neutrino and one charged lepton. Large destructive interferences make these decays very sensitive to the Z couplings to neutrinos. As the identified charged leptons can determine the neutrino flavors, these decays probe the universality of the Z couplings to neutrinos. The rare four-body processes could be accurately measured at future lepton colliders, leading to percent level precision.

  17. Higgs-boson and Z-boson flavor-changing neutral-current decays correlated with B-meson decays in the littlest Higgs model with T parity

    International Nuclear Information System (INIS)

    Han Xiaofang; Wang Lei; Yang Jinmin

    2008-01-01

    In the littlest Higgs model with T-parity new flavor-changing interactions between mirror fermions and the standard model (SM) fermions can induce various flavor-changing neutral-current decays for B-mesons, the Z-boson, and the Higgs boson. Since all these decays induced in the littlest Higgs with T-parity model are correlated, in this work we perform a collective study for these decays, namely, the Z-boson decay Z→bs, the Higgs-boson decay h→bs, and the B-meson decays B→X s γ, B s →μ + μ - , and B→X s μ + μ - . We find that under the current experimental constraints from the B-decays, the branching ratios of both Z→bs and h→bs can still deviate from the SM predictions significantly. In the parameter space allowed by the B-decays, the branching ratio of Z→bs can be enhanced up to 10 -7 (about one order above the SM prediction) while h→bs can be much suppressed relative to the SM prediction (about one order below the SM prediction).

  18. Alpha decay 225Ac→221Fr

    International Nuclear Information System (INIS)

    Kudrya, S.A.; Sergienko, V.A.; Gorozhankin, V.M.; Gromov, K.Ya.; Malikov, Sh.R.; Malov, L.A.; Fominykh, V.I.; Tsupko-Sitnikov, V.V.; Chumin, V.G.; Yakushev, E.A.

    2002-01-01

    In-depth investigation of (α-γ)-coincidences at the 225 Ac decay is carried out. Twenty-one new weak γ-rays are found; 18 γ-rays earlier ascribed to the 225 Ac decay are not confirmed. The quantitative analysis of the (α-γ)-coincidences makes it possible to find the intensity of population of 221 Fr levels by the α decay and multipolarities of five weak γ-transitions. The conversion electron spectrum is investigated in the range of 5-24 keV with a high (some 20 eV) energy resolution. A new M1 type 10.6-keV γ-transition is found. The proposed 225 Ac decay scheme includes 31 excited 221 Fr states. Parities are established for 16 of them. Possible spin values are proposed for 221 Fr levels. Properties of excited 221 Fr states are satisfactorily described by the quasiparticle-phonon nuclear model without the assumption of static octupole deformation

  19. Observation of charmless hadronic B decays

    Science.gov (United States)

    Buskulic, D.; de Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J.-P.; Lucotte, A.; Minard, M.-N.; Nief, J.-Y.; Odier, P.; Pietrzyk, B.; Casado, M. P.; Chmeissani, M.; Crespo, J. M.; Delfino, M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, Ll.; Juste, A.; Martinez, M.; Orteu, S.; Padilla, C.; Park, I. C.; Pascual, A.; Perlas, J. A.; Riu, I.; Sanchez, F.; Teubert, F.; Colaleo, A.; Creanza, D.; de Palma, M.; Gelao, G.; Girone, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Marinelli, N.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Alemany, R.; Bazarko, A. O.; Bonvicini, G.; Bright-Thomas, P.; Cattaneo, M.; Comas, P.; Coyle, P.; Drevermann, H.; Forty, R. W.; Frank, M.; Hagelberg, R.; Harvey, J.; Janot, P.; Jost, B.; Kneringer, E.; Knobloch, J.; Lehraus, I.; Lutters, G.; Martin, E. B.; Mato, P.; Minten, A.; Miquel, R.; Mir, Ll. M.; Moneta, L.; Oest, T.; Pacheco, A.; Pusztaszeri, J.-F.; Ranjard, F.; Rensing, P.; Rizzo, G.; Rolandi, L.; Schlatter, D.; Schmelling, M.; Schmitt, M.; Schneider, O.; Tejessy, W.; Tomalin, I. R.; Venturi, A.; Wachsmuth, H.; Wagner, A.; Ajaltouni, Z.; Barrès, A.; Boyer, C.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Rosnet, P.; Rossignol, J.-M.; Fearnley, T.; Hansen, J. B.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Nilsson, B. S.; Rensch, B.; Wäänänen, A.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Bourdon, P.; Rougé, A.; Rumpf, M.; Valassi, A.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Focardi, E.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Jaffe, D. E.; Antonelli, A.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Casper, D.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Curtis, L.; Dorris, S. J.; Halley, A. W.; Knowles, I. G.; Lynch, J. G.; O'Shea, V.; Raine, C.; Reeves, P.; Scarr, J. M.; Smith, K.; Teixeira-Dias, P.; Thompson, A. S.; Thomson, F.; Thorn, S.; Turnbull, R. M.; Becker, U.; Geweniger, C.; Graefe, G.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E. E.; Putzer, A.; Schmidt, M.; Sommer, J.; Stenzel, H.; Tittel, K.; Werner, S.; Wunsch, M.; Abbaneo, D.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Dornan, P. J.; Moutoussi, A.; Nash, J.; Sedgbeer, J. K.; Stacey, A. M.; Williams, M. D.; Dissertori, G.; Girtler, P.; Kuhn, D.; Rudolph, G.; Betteridge, A. P.; Bowdery, C. K.; Colrain, P.; Crawford, G.; Finch, A. J.; Foster, F.; Hughes, G.; Sloan, T.; Williams, M. I.; Galla, A.; Giehl, I.; Greene, A. M.; Jakobs, K.; Kleinknecht, K.; Quast, G.; Renk, B.; Rohne, E.; Sander, H.-G.; van Gemmeren, P.; Zeitnitz, C.; Aubert, J. J.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Bujosa, G.; Calvet, D.; Carr, J.; Diaconu, C.; Etienne, F.; Konstantinidis, N.; Payre, P.; Rousseau, D.; Talby, M.; Sadouki, A.; Thulasidas, M.; Trabelsi, K.; Aleppo, M.; Ragusa, F.; Bauer, C.; Berlich, R.; Blum, W.; Büscher, V.; Dietl, H.; Dydak, F.; Ganis, G.; Gotzhein, C.; Kroha, H.; Lütjens, G.; Lutz, G.; Männer, W.; Moser, H.-G.; Richter, R.; Rosado-Schlosser, A.; Schael, S.; Settles, R.; Seywerd, H.; Denis, R. St.; Stenzel, H.; Wiedenmann, W.; Wolf, G.; Boucrot, J.; Callot, O.; Choi, Y.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Höcker, A.; Jacholkowska, A.; Jacquet, M.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Nikolic, I.; Park, H. J.; Schune, M.-H.; Simion, S.; Veillet, J.-J.; Videau, I.; Zerwas, D.; Azzurri, P.; Bagliesi, G.; Batignani, G.; Bettarini, S.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Ciulli, V.; Dell'Orso, R.; Fantechi, R.; Ferrante, I.; Foà, L.; Forti, F.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Sanguinetti, G.; Sciabà, A.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Vannini, C.; Verdini, P. G.; Walsh, J.; Blair, G. A.; Bryant, L. M.; Cerutti, F.; Chambers, J. T.; Gao, Y.; Green, M. G.; Medcalf, T.; Perrodo, P.; Strong, J. A.; von Wimmersperg-Toeller, J. H.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Haywood, S.; Maley, P.; Norton, P. R.; Thompson, J. C.; Wright, A. E.; Bloch-Devaux, B.; Colas, P.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Marx, B.; Perez, P.; Rander, J.; Renardy, J.-F.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Trabelsi, A.; Vallage, B.; Black, S. N.; Dann, J. H.; Johnson, R. P.; Kim, H. Y.; Litke, A. M.; McNeil, M. A.; Taylor, G.; Booth, C. N.; Boswell, R.; Brew, C. A. J.; Cartwright, S.; Combley, F.; Koksal, A.; Letho, M.; Newton, W. M.; Reeve, J.; Thompson, L. F.; Böhrer, A.; Brandt, S.; Cowan, G.; Grupen, C.; Minguet-Rodriguez, J.; Rivera, F.; Saraiva, P.; Smolik, L.; Stephan, F.; Apollonio, M.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Musolino, G.; Rothberg, J.; Wasserbaech, S.; Armstrong, S. R.; Elmer, P.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; González, S.; Grahl, J.; Greening, T. C.; Hayes, O. J.; Hu, H.; McNamara, P. A.; Nachtman, J. M.; Orejudos, W.; Pan, Y. B.; Saadi, Y.; Scott, I. J.; Walsh, A. M.; Wu, Sau Lan; Wu, X.; Yamartino, J. M.; Zheng, M.; Zobernig, G.; Aleph Collaboration

    1996-02-01

    Four candidates for charmless hadronic B decay are observed in a data sample of four million hadronic Z decays recorded by the ALEPH detector at LEP. The probability that these events come from background sources is estimated to be less than 10 -6. The average branching ratio of weakly decaying B hadrons (a mixture of B d0, B s0 and Λb weighted by their production cross sections and lifetimes, here denoted B) into two long-lived charged hadrons (pions, kaons or protons) is measured to be Br(B → h +h -) = (1.7 -0.7+1.0 ± 0.2) × 10 -5. The relative branching fraction {Br( B d(s)0 → π +π -(K -)) }/{Br( B d(s)0 → h +h -) } is measured to be 1.0 -0.3 -0.1+0.0 +0.0. In addition, branching ratio upper limits are obtained for a variety of exclusive charmless hadronic two-body decays of B hadrons.

  20. Study of the decay asymmetry parameter and CP violation parameter in the Lambda(c)+ ---> Lambda pi+ decay

    Energy Technology Data Exchange (ETDEWEB)

    Link, J.M.; Yager, P.M.; /UC, Davis; Anjos, J.C.; Bediaga, I.; Castromonte, C.; Machado, A.A.; Magnin, J.; Massafferri, A.; de Miranda, J.M.; Pepe, I.M.; Polycarpo, E.; dos Reis, A.C.; /Rio de Janeiro, CBPF; Carrillo, S.; Casimiro, E.; Cuautle, E.; Sanchez-Hernandez, A.; Uribe, C.; Vazquez, F.; /CINVESTAV, IPN; Agostino, L.; Cinquini, L.; Cumalat,; /Colorado U. /Fermilab /Frascati /Guanajuato U. /Illinois U., Urbana /Indiana U. /Korea U. /Kyungpook Natl. U. /INFN, Milan /Milan U. /North Carolina U. /Pavia U. /INFN,

    2005-09-01

    Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement of the weak decay-asymmetry parameter a{sub {Lambda}{sub c}} in {Lambda}{sub c}{sup +} {yields} {Lambda}{pi}{sup +} decay. Comparing particle with antiparticle decays, we obtain the first measurement of the CP violation parameter {Alpha} {triple_bond} a{sub {Lambda}{sub c}} + a{sub {ovr {Lambda}{sub c}}}/a{sub {Lambda}{sub c}} - a{sub {ovr {Lambda}{sub c}}}. We obtain a{sub {Lambda}{sub c}} = -0.78 {+-} 0.16 {+-} 0.13 and {Alpha} = -0.07 {+-} 0.19 {+-} 0.12 where errors are statistical and systematic.

  1. The law of radioactive decay

    International Nuclear Information System (INIS)

    Bouyrie, G

    2004-01-01

    This article deals with the law of radioactive decay (Rutherford-Sody's law) and the way to explain it to high-school or grammar-school students. The mathematical content of the law is recalled and its experimental validation is proposed through the study of the decay of a population of radon-220 atoms. The analysis of the experimental data is made easier by using software such as Generis, Regressi or even Excel

  2. Polarization bremsstrahlung in α decay

    International Nuclear Information System (INIS)

    Amusia, M. Ya.; Zon, B. A.; Kretinin, I. Yu.

    2007-01-01

    A mechanism of formation of electromagnetic radiation that accompanies α decay and is associated with the emission of photons by electrons of atomic shells due to the scattering of α particles by these atoms (polarization bremsstrahlung) is proposed. It is shown that, when the photon energy is no higher than the energy of K electrons of an atom, polarization bremsstrahlung makes a significant contribution to the bremsstrahlung in α decay

  3. Beta decay of polarized nuclei and the decay asymmetry of 8Li

    International Nuclear Information System (INIS)

    Bigelow, R.; Freedman, S.J.; Napolitano, J.; Quin, P.A.

    1985-01-01

    Under certain conditions, it is possible to produce vector-polarized radioactive nuclei in reactions with a polarized projectile and an unpolarized target. Using the intense polarized beams at the University of Wisconsin, the authors have begun a program to study the weak interaction through the beta decay of polarized nuclei produced in this way. Such experiments bear on tests of CVC in light nuclei, sensitive searches for second-class weak currents, and measurements of the weak vector-coupling constant. One may also deduce the values of certain matrix elements. Our effort is presently centering on a study of the energy dependence of the beta-decay asymmetry of 8 Li

  4. Study of the decay asymmetry parameter and CP violation parameter in the Λc+→Λπ decay

    Science.gov (United States)

    FOCUS Collaboration; Link, J. M.; Yager, P. M.; Anjos, J. C.; Bediaga, I.; Castromonte, C.; Machado, A. A.; Magnin, J.; Massafferri, A.; de Miranda, J. M.; Pepe, I. M.; Polycarpo, E.; Dos Reis, A. C.; Carrillo, S.; Casimiro, E.; Cuautle, E.; Sánchez-Hernández, A.; Uribe, C.; Vázquez, F.; Agostino, L.; Cinquini, L.; Cumalat, J. P.; O'Reilly, B.; Segoni, I.; Stenson, K.; Butler, J. N.; Cheung, H. W. K.; Chiodini, G.; Gaines, I.; Garbincius, P. H.; Garren, L. A.; Gottschalk, E.; Kasper, P. H.; Kreymer, A. E.; Kutschke, R.; Wang, M.; Benussi, L.; Bertani, M.; Bianco, S.; Fabbri, F. L.; Pacetti, S.; Zallo, A.; Reyes, M.; Cawlfield, C.; Kim, D. Y.; Rahimi, A.; Wiss, J.; Gardner, R.; Kryemadhi, A.; Chung, Y. S.; Kang, J. S.; Ko, B. R.; Kwak, J. W.; Lee, K. B.; Cho, K.; Park, H.; Alimonti, G.; Barberis, S.; Boschini, M.; Cerutti, A.; D'Angelo, P.; Dicorato, M.; Dini, P.; Edera, L.; Erba, S.; Inzani, P.; Leveraro, F.; Malvezzi, S.; Menasce, D.; Mezzadri, M.; Moroni, L.; Pedrini, D.; Pontoglio, C.; Prelz, F.; Rovere, M.; Sala, S.; Davenport, T. F.; Arena, V.; Boca, G.; Bonomi, G.; Gianini, G.; Liguori, G.; Lopes Pegna, D.; Merlo, M. M.; Pantea, D.; Ratti, S. P.; Riccardi, C.; Vitulo, P.; Göbel, C.; Olatora, J.; Hernandez, H.; Lopez, A. M.; Mendez, H.; Paris, A.; Quinones, J.; Ramirez, J. E.; Zhang, Y.; Wilson, J. R.; Handler, T.; Mitchell, R.; Engh, D.; Hosack, M.; Johns, W. E.; Luiggi, E.; Moore, J. E.; Nehring, M.; Sheldon, P. D.; Vaandering, E. W.; Webster, M.; Sheaff, M.

    2006-03-01

    Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement of the weak decay-asymmetry parameter αΛ_c in Λc+→Λπ decay. Comparing particle with antiparticle decays, we obtain the first measurement of the CP violation parameter A≡αΛ_c+ααΛ_c-α. We obtain αΛ_c=-0.78±0.16±0.19 and A=-0.07±0.19±0.24 where errors are statistical and systematic.

  5. On Error Analysis of ORIGEN Decay Data Library Based on ENDF/B-VII.1 via Decay Heat Estimation after a Fission Event

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Do Heon; Gil, Choong-Sup; Lee, Young-Ouk [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The method is strongly dependent on the available nuclear structure data, i.e., fission product yield data and decay data. Consequently, the improvements in the nuclear structure data could have guaranteed more reliable decay heat estimation for short cooling times after fission. The SCALE-6.1.3 code package includes the ENDF/B-VII.0-based fission product yield data and ENDF/B-VII.1-based decay data libraries for the ORIGEN-S code. The generation and validation of the new ORIGEN-S yield data libraries based on the recently available fission product yield data such as ENDF/B-VII.1, JEFF-3.1.1, JENDL/FPY-2011, and JENDL-4.0 have been presented in the previous study. According to the study, the yield data library in the SCALE-6.1.3 could be regarded as the latest one because it resulted in almost the same outcomes as the ENDF/B-VII.1. A research project on the production of the nuclear structure data for decay heat estimation of nuclear fuel has been carried out in Korea Atomic Energy Research Institute (KAERI). The data errors contained in the ORIGEN-S decay data library of SCALE-6.1.3 have been clearly identified by their changing variables. Also, the impacts of the decay data errors have been analyzed by estimating the decay heats for the fission product nuclides and their daughters after {sup 235}U thermal-neutron fission. Although the impacts of decay data errors are quite small, it reminds us the possible importance of decay data when estimating the decay heat for short cooling times after a fission event.

  6. Δ-decay in the Skyrme model

    International Nuclear Information System (INIS)

    Verschelde, H.

    1988-01-01

    The Δ-decay matrix element is calculated while carefully paying attention to ordering problems. The decay width obtained is too large by a factor of four. Arguments are given that this discrepancy is not a defect of the Skyrme model but a consequence of the rigid rotor quantization. (orig.)

  7. Creating perturbations from a decaying field during inflation

    DEFF Research Database (Denmark)

    Mazumdar, A.; Wang, L.

    2013-01-01

    Typically, the fluctuations generated from a decaying field during inflation do not contribute to the large scale structures. In this paper, we provide an example where it is possible for a field which slowly rolls and then decays during inflation to create all the matter perturbations with a sli......Typically, the fluctuations generated from a decaying field during inflation do not contribute to the large scale structures. In this paper, we provide an example where it is possible for a field which slowly rolls and then decays during inflation to create all the matter perturbations...

  8. Calculational tracking of decay heat for FFTF plant

    International Nuclear Information System (INIS)

    Cillan, T.F.; Carter, L.L.

    1985-01-01

    A detailed calculational monitoring of decay heat for each assembly on the Fast Flux Test Facility (FFTF) plant is obtained by utilizing a decay heat data base and user friendly computer programs to access the data base. Output includes the time-dependent decay heat for an assembly or a specific set of assemblies, and optional information regarding the curies of activated nuclides along the axial length of the assembly. The decay heat data base is updated periodically, usually at the end of each irradiation cycle. 1 ref., 2 figs

  9. Search for hidden Higgs decay in ATLAS detector

    International Nuclear Information System (INIS)

    Gabrielli, A.

    2013-01-01

    In this paper, a brief overview of the search for the Higgs boson in Hidden Valley models is given. Hidden Valley models predict Higgs decays to neutral particles, which can be also long lived with decay paths comparable to the LHC detectors dimensions. Decay final states consist of collimated leptons (Lepton Jets). Results are presented of a search for Higgs decays to long lived particles in the ATLAS detector at the LHC, based on 1.92 fb −1 data collected during 2011 at a 7TeV center-of-mass energy.

  10. Radiative decays of the Upsilon(1S) meson

    International Nuclear Information System (INIS)

    Besson, D.Z.

    1986-01-01

    Using the CLEO detector at the Cornell Electron Storage Ring, the author is able to measure the QCD scaling parameter Λ/sub MS/ as well as the strong coupling constant α/sub s/ through a measurement of the direct photon energy spectrum resulting from decays of the Upsilon(1S) meson. The author finds fair agreement with previous work. In addition, the author sets limits on exclusive two-body radiative decays of the Upsilon(1S) meson and see no evidence for the type of such two-body decays which are observed in psi decays

  11. ATLAS helicity analyses in beauty hadron decays

    CERN Document Server

    Smizanska, M

    2000-01-01

    The ATLAS detector will allow a precise spatial reconstruction of the kinematics of B hadron decays. In combination with the efficient lepton identification applied already at trigger level, ATLAS is expected to provide large samples of exclusive decay channels cleanly separable from background. These data sets will allow spin-dependent analyses leading to the determination of production and decay parameters, which are not accessible if the helicity amplitudes are not separated. Measurement feasibility studies for decays B/sub s //sup 0/ to J/ psi phi and Lambda /sub b//sup 0/ to Lambda J/ psi , presented in this document, show the experimental precisions that can be achieved in determination of B/sub s//sup 0/ and Lambda /sub b //sup 0/ characteristics. (19 refs).

  12. Quarkonium decays: Testing the 3-gluon vertex

    International Nuclear Information System (INIS)

    Koller, K.; Walsh, T.F.; Zerwas, P.M.; Technische Hochschule Aachen

    1980-12-01

    We study the 3-jet decays of S and P-wave quarkonia with C = +. If observed, some of these will offer a way of seeing the 3G vertex of QCD via 1 Ssub(o), 3 Psub(o), 3 P 2 (Qanti Q) → GGG + Gqanti q → 3 jets. (As is well-known, cancellations reduce 3 P 1 (anti Q) → GGG.) We elaborate in detail the S-wave decay as it is expected to show all the characteristic features of orthoquarkonium decays into 4 jets, 3 S 1 (Qanti Q) → GGGG + GGqanti q → 4 jets which we will comment upon. These quarkonium decays offer a very clear signal for QCD as a non-abelian local gauge field theory with color-charged gluons. (orig.)

  13. Half-life predictions for decay modes of superheavy nuclei

    International Nuclear Information System (INIS)

    Duarte, S.B.; Tavares, O.A.P.; Goncalves, M.; Rodriguez, O.; Guzman, F.; Barbosa, T.N.; Garcia, F.; Dimarco, A.

    2004-09-01

    We applied the Effective Liquid Drop Model (ELDM) to predict the alpha-decay, cluster emission and cold fission half-life-values of nuclei in the region of Superheavy Elements (SHE). The present calculations have been made in the region of the ZN-plane defined by 155 <=N <=220 and 110<=Z<=135. Shell effects are included via the Q-value of the corresponding decay case. We report the results of a systematic calculation of the half-life for the three nuclear decay modes in a region of the ZN-plane where superheavy elements are expected to be found. Results have shown that, among the decay modes investigated here, the alpha decay is the dominant one. i.e, the decay mode of smallest half-lives. Half-life predictions for alpha decay, cluster emission and cold fission for the isotopic family of the most recent SHE detected of Z=115 and for the isotopic family of the already consolidated SHE of Z=111 are presented. (author)

  14. An application program for fission product decay heat calculations

    International Nuclear Information System (INIS)

    Pham, Ngoc Son; Katakura, Jun-ichi

    2007-10-01

    The precise knowledge of decay heat is one of the most important factors in safety design and operation of nuclear power facilities. Furthermore, decay heat data also play an important role in design of fuel discharges, fuel storage and transport flasks, and in spent fuel management and processing. In this study, a new application program, called DHP (Decay Heat Power program), has been developed for exact decay heat summation calculations, uncertainty analysis, and for determination of the individual contribution of each fission product. The analytical methods were applied in the program without any simplification or approximation, in which all of linear and non-linear decay chains, and 12 decay modes, including ground state and meta-stable states, are automatically identified, and processed by using a decay data library and a fission yield data file, both in ENDF/B-VI format. The window interface of the program is designed with optional properties which is very easy for users to run the code. (author)

  15. Nuclear physics with hyperons

    International Nuclear Information System (INIS)

    Povh, B.

    1981-01-01

    Results of hypernuclear spectroscopy and their interpretations are presented. The kinematical properties and, in particular, the distortion in strangeness exchange reactions are considered and experimental methods developed for hypernuclear spectroscopy discussed. The present understanding and knowledge of the Λ-nucleus interaction obtained from classical emulsion work on the ground state of light hypernuclei and the systematic study of the (K - , π - ) reaction on nuclei in more recent counter experiments are reviewed. The problem of the quasiparticle behaviour in nuclear matter is considered in the light of interactions. Finally recent results on the Σ-nucleus interactions are presented. (U.K.)

  16. Rare B decays and new physics studies

    International Nuclear Information System (INIS)

    Long, Owen

    2006-01-01

    I present a review of using rare B decays to search for physics beyond the Standard Model. B decays that proceed either through annihilation or loop topologies at leading order in the Standard Model provide unique probes in the search for new physics. The latest experimental results from the B factories (Babar and Belle) and the Tevatron experiments (CDF and D0) on rare decays and their impact on various scenarios for new physics will be presented. (author)

  17. Can $\\beta$-decay probe excited state halos?

    CERN Multimedia

    2002-01-01

    In the first experiment at the newly constructed ISOLDE Facility the first-forbidden $\\beta$-decay of $^{17}$Ne into the first excited state of $^{17}$F has been measured. It is a factor two faster than the corresponding mirror decay and thus gives one of the largest recorded asymmetries for $\\beta$-decays feeding bound final states. Shell-model calculations can only reproduce the asymmetry if the halo structure of the $^{17}$F state is taken into account.

  18. Nuclear decay data measurements at the INEL ISOL facility

    International Nuclear Information System (INIS)

    Greenwood, R.C.; Helmer, R.G.; Putnam, M.H.; Struttmann, D.A.; Watts, K.D.

    1991-01-01

    In recent years, the use of the mass separation technique coupled on-line to a source of fission product nuclides has provided a wealth of new information on the nuclear decay properties of such nuclides. In addition to their relevance in basic studies of nuclear properties of neutron-rich nuclei, the fission product nuclides as a group, because of their intimate link with energy production in fission reactors, occupy a unique position in the field of applied nuclear decay data. Further, in addition to their critical role in nuclear reactor technology (decay heat source term, environmental concerns, etc.), such data have important applications in astrophysical calculations involving the rapid neutron capture process (r-process) of elemental synthesis in stellar environments. The scope of the nuclear decay data measurements being undertaken using the Idaho National Engineering Laboratory's (INEL) isotope separation on-line (ISOL) facility is focused on a systematic study of the gross nuclear decay properties of short-lived fission product isotopes, i.e., ground-state half-lives, beta-decay energies and beta-decay feeding (or beta-strength) distributions. In this paper, the authors discuss the results of new measurements of beta-decay energies and feeding distributions

  19. Proton decay in the super-world

    International Nuclear Information System (INIS)

    Raby, S.

    1986-01-01

    Predictions are elaborated for nucleon decay in supersymmetric grand unified theories (SUSY GUT's). A minimal SU 5 SUSY GUT is described, as well as SU 5 breaking. The low energy theory and breaking of supersymmetry are discussed. It is concluded that nucleon decay in SUSY GUT's would be dominated by p → K + anti nu/sub μ/ and n → K 0 anti nu/sub μ/. There are ranges in parameter space for which other decay modes may be significant or may even dominate, it is found. It is noted that minimal SUSY GUT's typically predict a value of sin 2 θ/sub w/ of order .233. 20 refs., 7 figs

  20. Neutrino signals from dark matter decay

    International Nuclear Information System (INIS)

    Covi, Laura; Grefe, Michael; Ibarra, Alejandro; Tran, David

    2009-12-01

    We investigate different neutrino signals from the decay of dark matter particles to determine the prospects for their detection, and more specifically if any spectral signature can be disentangled from the background in present and future neutrino observatories. If detected, such a signal could bring an independent confirmation of the dark matter interpretation of the dramatic rise in the positron fraction above 10 GeV recently observed by the PAMELA satellite experiment and offer the possibility of distinguishing between astrophysical sources and dark matter decay or annihilation. In combination with other signals, it may also be possible to distinguish among different dark matter decay channels. (orig.)

  1. Neutrino signals from dark matter decay

    Energy Technology Data Exchange (ETDEWEB)

    Covi, Laura; Grefe, Michael [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ibarra, Alejandro; Tran, David [Technische Univ. Muenchen, Garching (Germany). Physik-Department T30d

    2009-12-15

    We investigate different neutrino signals from the decay of dark matter particles to determine the prospects for their detection, and more specifically if any spectral signature can be disentangled from the background in present and future neutrino observatories. If detected, such a signal could bring an independent confirmation of the dark matter interpretation of the dramatic rise in the positron fraction above 10 GeV recently observed by the PAMELA satellite experiment and offer the possibility of distinguishing between astrophysical sources and dark matter decay or annihilation. In combination with other signals, it may also be possible to distinguish among different dark matter decay channels. (orig.)

  2. Precision measurements in nuclear beta decay

    Energy Technology Data Exchange (ETDEWEB)

    Naviliat-Cuncic, Oscar, E-mail: naviliat@nscl.msu.edu [Michigan State University, National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy (United States)

    2013-03-15

    Precision measurements in nuclear beta decay provide sensitive means to determine the fundamental coupling of charged fermions to weak bosons and to test discrete symmetries in the weak interaction. The main motivation of such measurements is to find deviations from Standard Model predictions as possible indications of new physics. I focus here on two topics related to precision measurements in beta decay, namely: (i) the determination of the V{sub ud} element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix from nuclear mirror transitions and (ii) selected measurements of time reversal violating correlations in nuclear and neutron decays. These topics complement those presented in other contributions to this conference.

  3. Decays of J/psi (3100) to baryon final states

    International Nuclear Information System (INIS)

    Eaton, M.W.

    1982-05-01

    We present results for the decays of psi(3100) into baryon and hyperon final states. The sample studied here consists of 1.3 million produced psi decays. The decays into nonstrange baryons agree well with currently established results, but with better statistics. In addition, significant resonance formation in multibody final states is observed. The decay psi → anti ppγ, the first direct photon decay of the psi involving baryons in the final state, is presented and the theoretical implications of the decays are briefly explored. Several new decays of the psi involving strange baryons are explored, including the first observations of three body final states involving hyperons. The I-spin symmetry of the strong decay psi → baryons has clearly been observed. The reduced matrix elements for psi → B anti B are presented for final states of different SU(3) content. The B 8 anti B 8 results are in excellent agreement with the psi being an SU(3) singlet as are the results for psi → B 10 anti B 10 . We present the first evidence for the SU(3) violating decays of the type psi → B 8 anti B 10 + c.c.. Angular distributions for psi → B 8 anti B 8 are presented and compared with theoretical predictions. Statistics are limited, but the data tends to prefer other than a 1 + Cos 2 theta distribution

  4. Observable signatures of inflaton decays

    Energy Technology Data Exchange (ETDEWEB)

    Battefeld, Diana; Battefeld, Thorsten [Institute for Astrophysics, University of Goettingen, Friedrich Hund Platz 1, D-37077 Gottingen (Germany); Giblin, John T. Jr.; Pease, Evan K., E-mail: dbattefe@astro.physik.uni-goettingen.de, E-mail: tbattefe@astro.physik.uni-goettingen.de, E-mail: giblinj@kenyon.edu, E-mail: peasee@kenyon.edu [Department of Physics, Kenyon College, Gambier, OH 43022, U.S.A (United States)

    2011-02-01

    We numerically compute features in the power-spectrum that originate from the decay of fields during inflation. Using a simple, phenomenological, multi-field setup, we increase the number of fields from a few to thousands. Whenever a field decays, its associated potential energy is transferred into radiation, causing a jump in the equation of state parameter and mode mixing at the perturbed level. We observe discrete steps in the power-spectrum if the number of fields is low, in agreement with analytic arguments in the literature. These features become increasingly smeared out once many fields decay within a given Hubble time. In this regime we confirm the validity of the analytic approach to staggered inflation, which is based on a coarse-graining procedure. Our numerical approach bridges the aforementioned analytic treatments, and can be used in more complicated scenarios.

  5. Results on semileptonic D0 and D/sub s/ decays and evidence for non-D/bar D/ decays of the /psi/ (3770)

    International Nuclear Information System (INIS)

    Schindler, R.H.

    1988-12-01

    This paper discusses the following topics: Observation of Cabibbo suppressed semileptonic D 0 decays; Search for D/sub s/ semileptonic decays; and Preliminary evidence for non-D/bar D/ decays of the /psi/ (3770). 4 refs., 3 figs., 2 tabs

  6. Sequential decay of Reggeons

    International Nuclear Information System (INIS)

    Yoshida, Toshihiro

    1981-01-01

    Probabilities of meson production in the sequential decay of Reggeons, which are formed from the projectile and the target in the hadron-hadron to Reggeon-Reggeon processes, are investigated. It is assumed that pair creation of heavy quarks and simultaneous creation of two antiquark-quark pairs are negligible. The leading-order terms with respect to ratio of creation probabilities of anti s s to anti u u (anti d d) are calculated. The production cross sections in the target fragmentation region are given in terms of probabilities in the initial decay of the Reggeons and an effect of manyparticle production. (author)

  7. Hyperon decays and spectrum generating SU(3)

    International Nuclear Information System (INIS)

    Teese, R.B.; Boehm, A.

    1976-02-01

    The research program described in this review is aimed at describing the properties of relativistic one-hadron systems by an algebra of observables, in analogy to the nonrelativistic description of atoms. This formalism has recently been applied to the leptonic and semi-leptonic decays of pseudoscalar mesons, and was shown to be capable of predicting both the suppression of strangeness changing decays and the value of the form factor ratio xi in K/sub l 3 / decay. A preliminary description of the leptonic decays of hyperons indicates that second class matrix elements are predicted as a consequence of a precise formulation of SU(3) symmetry breaking. A chi 2 -fit to the experimental data indicates that this preliminary model is an improvement over the usual Cabibbo model, and points the way for further theoretical work. It is hoped that this program will lead to a model for the leptonic decays of hadrons which improves upon the results of the Cabibbo model and which explains some of the assumptions of that model

  8. Decaying dark matter and the PAMELA anomaly

    International Nuclear Information System (INIS)

    Ibarra, Alejandro; Tran, David

    2009-01-01

    Astrophysical and cosmological observations do not require the dark matter particles to be absolutely stable. If they are indeed unstable, their decay into positrons might occur at a sufficiently large rate to allow the indirect detection of dark matter through an anomalous contribution to the cosmic positron flux. In this paper we discuss the implications of the excess in the positron fraction recently reported by the PAMELA collaboration for the scenario of decaying dark matter. To this end, we have performed a model-independent analysis of possible signatures by studying various decay channels in the case of both a fermionic and a scalar dark matter particle. We find that the steep rise in the positron fraction measured by PAMELA at energies larger than 10 GeV can naturally be accommodated in several realizations of the decaying dark matter scenario. The data point toward a rather heavy dark matter particle, m DM ∼> 300 GeV, which preferentially decays directly into first or second generation charged leptons with a lifetime τ DM ∼ 10 26 s

  9. Measurement of CP Violation Parameters in B Quark Decays to Charm Anticharm Down Quarks, Exclusive Decays at the BABAR Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Albert, Justin E.

    2003-04-03

    The BABAR experiment at SLAC provides an opportunity for measurement of CP violation in B decays. A measurement of time-dependent CP violating asymmetries using exclusive B meson decays where the b quark decays to c{bar c}d (including B{sup 0} {yields} D*{sup +}D*{sup -} and B{sup 0} {yields} D*{sup {+-}}D{sup {-+}} decays) is presented here. This is the first measurement of CP violation in a mode sensitive to the Unitarity Triangle parameter sin2{beta} outside of decays containing charmonium. It provides a comparison to measurements of sin2{beta} using b {yields} c{bar c}s, and permits an observation into potential new physics sources of CP violation, such as supersymmetry, via differences between these measurements and those of B{sup 0} {yields} J/{psi} K{sub S}{sup 0} as statistics of reconstructed neutral B decays to D{sup (*)+} D{sup (*)-} increase. The measured value of the time-dependent CP violating asymmetries are: S = 0.38 {+-} 0.88(stat) {+-} 0.12(syst) and C = -0.30 {+-} 0.50(stat) {+-} 0.13(syst) for B{sup 0} {yields} D*{sup -} D{sup +}; S = -0.43 {+-} 1.41(stat) {+-} 0.23(syst) and C = 0.53 {+-} 0.74(stat) {+-} 0.15(syst) for B{sup 0} {yields} D*{sup +} D{sup -}; and S = -0.05 {+-} 0.45(stat) {+-} 0.05(syst) and C = 0.12 {+-} 0.30(stat) {+-} 0.05(syst) for B{sup 0} {yields} D*{sup -} D{sup +}; where S corresponds to CP violation in the interference of mixing and decay and C corresponds to CP violation in decay.

  10. Decay Mode Solutions for Kadomtsev-Petviashvili Equation

    International Nuclear Information System (INIS)

    Fan Guohao; Deng Shufang; Zhang Meng

    2012-01-01

    The decay mode solutions for the Kadomtsev-Petviashvili (KP) equation are derived by Hirota method (direct method). The decay mode solution is a new set of analytical solutions with Airy function. (general)

  11. Precise predictions for CP asymmetries in B decays

    Energy Technology Data Exchange (ETDEWEB)

    Nierste, Ulrich; Frings, Philipp [Institut fuer Theoretische Teilchenphysik, KIT, Karlsruhe (Germany)

    2016-07-01

    The extraction of fundamental CP phases from B{sub d} or B{sub s} decays to charmonium is affected by penguin contributions. We show how these contributions can be calculated with dynamical QCD-based methods and present our predictions for a variety of decay modes and briefly discuss branching ratios in B→ DD decays.

  12. Gamma-ray lines from radiative dark matter decay

    International Nuclear Information System (INIS)

    Garny, Mathias; Ibarra, Alejandro; Tran, David; Weniger, Christoph

    2011-01-01

    The decay of dark matter particles which are coupled predominantly to charged leptons has been proposed as a possible origin of excess high-energy positrons and electrons observed by cosmic-ray telescopes PAMELA and Fermi LAT. Even though the dark matter itself is electrically neutral, the tree-level decay of dark matter into charged lepton pairs will generically induce radiative two-body decays of dark matter at the quantum level. Using an effective theory of leptophilic dark matter decay, we calculate the rates of radiative two-body decays for scalar and fermionic dark matter particles. Due to the absence of astrophysical sources of monochromatic gamma rays, the observation of a line in the diffuse gamma-ray spectrum would constitute a strong indication of a particle physics origin of these photons. We estimate the intensity of the gamma-ray line that may be present in the energy range of a few TeV if the dark matter decay interpretation of the leptonic cosmic-ray anomalies is correct and comment on observational prospects of present and future Imaging Cherenkov Telescopes, in particular the CTA

  13. Topics on CP violation in B-meson decays

    International Nuclear Information System (INIS)

    Soares, J.M.

    1993-01-01

    In this work several independent topics on CP violation in the B-meson decays are addressed. To begin with, the present constraints on the parameters of the Cabibbo-Kobayashi-Maskawa (CKM) matrix are discussed. Then, I calculate the CP-violating asymmetry in the radiative decays of the charged B-mesons: it only appears at the 2-loop level, but it can be large in the b → dγ decays. At this point, the possibility of using these decays to measure the CKM entry |V td | will be studied. I also consider the decays of the neutral B-mesons: the strong correlation between the asymmetries in B 0 → ΨK S and the B 0 → π + π - is suggested as a powerful test of the standard model (a simple extension of the model is given where the correlation disappears). Finally, I address the question of observing direct CP violation in comparing these two asymmetries. An ambiguity that may arise is resolved due to the role that is played by penguin diagram contributions to the decay amplitudes

  14. Cavities/Tooth Decay

    Science.gov (United States)

    ... milk, ice cream, honey, sugar, soda, dried fruit, cake, cookies, hard candy and mints, dry cereal, and ... teeth can wear down and gums may recede, making teeth more vulnerable to root decay. Older adults ...

  15. Hadronic {tau} decays and QCD

    Energy Technology Data Exchange (ETDEWEB)

    Davier, M

    1999-12-01

    Hadronic decays of the {tau} lepton provide a clean source to study hadron dynamics in an energy regime dominated by resonances, with the interesting information captured in the spectral functions. Recent results on exclusive channels are reviewed. Inclusive spectral functions are the basis for QCD analyses, delivering an accurate determination of the strong coupling constant and quantitative information on nonperturbative contributions. Strange decays yield a determination of the strange quark mass. (author)

  16. Hadronic τ decays and QCD

    International Nuclear Information System (INIS)

    Davier, M.

    1999-12-01

    Hadronic decays of the τ lepton provide a clean source to study hadron dynamics in an energy regime dominated by resonances, with the interesting information captured in the spectral functions. Recent results on exclusive channels are reviewed. Inclusive spectral functions are the basis for QCD analyses, delivering an accurate determination of the strong coupling constant and quantitative information on nonperturbative contributions. Strange decays yield a determination of the strange quark mass. (author)

  17. Mitigation of radon and thoron decay products by filtration

    International Nuclear Information System (INIS)

    Wang Jin; Meisenberg, Oliver; Chen Yongheng; Karg, Erwin; Tschiersch, Jochen

    2011-01-01

    Inhalation of indoor radon ( 222 Rn) and thoron ( 220 Rn) decay products is the most important source of exposure to ionizing radiation for the human respiratory tract. Decreasing ventilation rates due to energy saving reasons in new buildings suggest additional active mitigation techniques to reduce the exposure in homes with high radon and thoron concentrations but poor ventilation. Filtration techniques with HEPA filters and simple surgical mask material have been tested for their potential to reduce the indoor exposure in terms of the total effective dose for mixed radon and thoron indoor atmospheres. The tests were performed inside an experimental room providing stable conditions. Filtration (at filtration rates of 0.2 h -1 and larger) removes attached radon and thoron decay products effectively but indoor aerosol as well. Therefore the concentration of unattached decay products (which have a higher dose coefficient) may increase. The decrease of the attached decay product concentrations could be theoretically described by a slowly decreasing exponential process. For attached radon decay products, it exhibited a faster but weaker removal process compared to attached thoron decay products (- 70% for attached radon decay products and - 80% for attached thoron decay products at a filtration rate of 0.5 h -1 with an HEPA filter). The concentration of unattached thoron decay products increased distinctly during the filtration process (+ 300%) while that of unattached radon decay products rose only slightly though at a much higher level (+ 17%). In the theoretical description these observed differences could be attributed to the different half-lives of the nuclides. Considering both effects, reduced attached and increased unattached decay product concentrations, filtration could significantly decrease the total effective dose from thoron whereas the overall effect on radon dose is small. A permanent filtration is recommended because of the slow decrease of the

  18. Beta-delayed particle decay of 17Ne

    International Nuclear Information System (INIS)

    Morton, A.C.; Chow, J.C.; King, J.D.; Boyd, R.N.; Bateman, N.P.T.; Buchmann, L.; D'Auria, J.M.; Davinson, T.; Dombsky, M.; Galster, W.; Gete, E.; Giesen, U.; Iliadis, C.; Jackson, K.P.; Powell, J.; Roy, G.; Shotter, A.

    2002-01-01

    The β-delayed particle decay of 17 Ne has been studied via proton-γ coincidences, time-of-flight measurements and the ''ratio-cut technique'', allowing cleanly-separated proton and α-particle spectra to be obtained. A complete set of proton and α branching ratios for the decay of 14 excited states in 17 F to the ground and excited states of 16 O and 13 N has been determined and branching ratios for the β decay of 17 Ne to these states have been deduced. From the branching ratios, f A t values and reduced Gamow-Teller matrix elements were calculated; no indication of isospin mixing in the isobaric analog state in 17 F was observed. From the measurement of proton-γ angular correlations, combined with the selection rules for an allowed β decay, we obtain J π =((1)/(2)) - for states at 8.436 and 9.450 MeV and ((3)/(2)) - for the state at 10.030 MeV in 17 F. Probabilities for the β-delayed pα decay to 12 C through the tails of the subthreshold 7.117 and 6.917 MeV states in 16 O have been calculated and the feasibility of using such decays to provide information about the rates for the E1 and E2 components of the 12 C(α,γ) 16 O reaction is discussed

  19. CP asymmetries in Strange Baryon Decays

    Science.gov (United States)

    Bigi, I. I.; Kang, Xian-Wei; Li, Hai-Bo

    2018-01-01

    While indirect and direct CP violation (CPV) has been established in the decays of strange and beauty mesons, no CPV has yet been found for baryons. There are different paths to finding CP asymmetry in the decays of strange baryons; they are all highly non-trivial. The HyperCP Collaboration has probed CPV in the decays of single Ξ and Λ [1]. We discuss future lessons from {{{e}}}+{{{e}}}- collisions at BESIII/BEPCII: probing decays of pairs of strange baryons, namely Λ, Σ and Ξ. Realistic goals are to learn about non-perturbative QCD. One can hope to find CPV in the decays of strange baryons; one can also dream of finding the impact of New Dynamics. We point out that an important new era will start with the BESIII/BEPCII data accumulated by the end of 2018. This also supports new ideas to trigger {{J}}/{{\\psi }}\\to \\bar{{{Λ }}}{{Λ }} at the LHCb collaboration. Supported by National Science Foundation (PHY-1520966), National Natural Science Foundation of China (11335009, 11125525), Joint Large-Scale Scientific Facility Funds of the NSFC and CAS (U1532257), the National Key Basic Research Program of China (2015CB856700), Key Research Program of Frontier Sciences, CAS, (QYZDJ-SSW-SLH003), XWK’s work is also supported by MOST (Taiwan) (104-2112-M-001-022)

  20. ENDF/B fission product decay data

    International Nuclear Information System (INIS)

    Rose, P.F.; Burrows, T.W.

    1976-08-01

    The fission product data have been organized by A-chains in order of ascending A from A = 72 to A = 167. The heading page is followed by more detailed information on the individual members of the chain in order of increasing Z and decreasing metastable state. The detailed information for each member includes the ENDF/B-IV File 1 comments and references if available and applicable to the decay data. Following the comments is a decay scheme of the nuclide tabulating the quantities T/sub 1 / 2 /, Q, branching ratio (BR), (E/sub γ/), (E/sub β/), and (E/sub α/). Uncertainties are given if available in the file. Independent fission yields are given, as well as thermal cross sections and resonance integrals as obtained from ENDF/B-IV. All energies listed in this publication are in keV, and all branching ratios (BR) sum to unity. If there are spectra in the decay data file, the decay scheme is followed by tables of photon, particle, and characteristic radiation. For cases in which the multipolarities could be obtained from the file the tables also contain information on x-rays, conversion electrons, and Auger electrons. Associated with the photon and particle radiation tables are the appropriate average energies per decay for each type of radiation, including neutrino radiation

  1. On the foundation of a variational principle for decaying systems

    International Nuclear Information System (INIS)

    Szasz, G.I.

    1976-01-01

    Taking into account the circumstances that the decay of an unstable microscopic system into two fragments is established by the counting of one of the decay products in a detector, the observed exponential decay law then asserts only knowledge of the spatiotemporal behaviour of the probability density (and therewith knowledge of the decaying state) at a large finite distance from the site of decay. We therefore formulate a variational principle, of which stationary functions show this decay behaviour. In addition to the resonant wave functions there are also solutions of the variational principle, which decrease exponentially with increasing distance, i.e., functions which could be used to describe the bound states. As the time-dependent treatment shows, the decaying states cannot occur in isolation in a scattering process. The mathematical characterisation of the decaying states via a variational principle is incorporated in a theory of open physical systems. In contradiction to the variational principle of Schroedinger our principle does not provide complete knowledge of the quantum states, but this is not needed in order to describe the decay. (orig.) [de

  2. On some rare weak decays of vector mesons

    International Nuclear Information System (INIS)

    Kurdadze, L.M.; Silagadze, Z.K.

    2000-01-01

    Some semileptonic weak decays of vector mesons are considered in the framework of the most popular quark models. Two the most popular models go give more elaborated estimates for the vector meson semileptonic decay rates are used. Unfortunately the predicted branching ratios are too small to make a study of these decays realistic at meson factories under construction [ru

  3. Isospin and quarks in nuclear beta-decay

    International Nuclear Information System (INIS)

    Wilkinson, D.H.

    1991-04-01

    This paper exposes in some detail the technical problems relating to the extraction of the vector coupling constant from the beta decay of complex nuclei. It also considers the extraction of the axial coupling constant from the beta-decay of the neutron. The internal consistency of all data relating to beta-decay, including that of the muon, is also examined, within the standard model, with a view to the possible intervention of W R . (Author) 52 refs., 4 figs., 2 tabs

  4. Photon and decay data libraries for ORIGEN2 code based on JENDL FP decay data file 2000

    CERN Document Server

    Katakura, J I

    2002-01-01

    Photon and decay data libraries for the ORIGEN2 code have been updated by using JENDL FP Decay Data File 2000 (JENDL/FPD-00). As for the decay data, half-lives, branching ratios and recoverable energy values have been replaced with those of the JENDL/FPD-00 file. The data of the photon library has been also replaced with those of the JENDL/FPD-00 file in which photon data of the nuclides without measured data are calculated with a theoretical method. Using the updated photon library, the calculation of photon spectrum at a short time after fission event is able to be made.

  5. On the 221 Rn → 221 Fr decay scheme

    International Nuclear Information System (INIS)

    Gromov, K.Ya.; Norseev, Yu.V.; Samatov, Zh.K.; Fominykh, V.I.; Chumin, V.G.; Kudrya, S.A.; Sergienko, V.A.

    2002-01-01

    The results of investigating the 221 Rnβ - - decay and the 225 Ac α-decay are compared. It is shown that 221 Fr levels at 145.9 and 393.2 keV are excited at the 221 Rn decay. Intensities and reduced probabilities of the β - - decay to the 221 Fr levels are determined. A conclusion is drawn that the parity of the 221 Rn ground state is positive

  6. Search for Bc+ decays to two charm mesons

    Directory of Open Access Journals (Sweden)

    R. Aaij

    2018-05-01

    Full Text Available A search for decays of Bc+ mesons to two charm mesons is performed for the first time using data corresponding to an integrated luminosity of 3.0fb−1, collected by the LHCb experiment in pp collisions at centre-of-mass energies of 7 and 8 TeV. The decays considered are Bc+→D(s(⁎+D‾(⁎0 and Bc+→D(s(⁎+D(⁎0, which are normalised to high-yield B+→D(s+D‾0 decays. No evidence for a signal is found and limits are set on twelve Bc+ decay modes.

  7. Radioactive-nuclide decay data in science and technology

    International Nuclear Information System (INIS)

    Reich, C.W.; Helmer, R.G.

    1975-01-01

    The scope of ENDF/B has recently been expanded to include radioactive-nuclide decay data. In this paper, the content and organization of the decay data which are included in ENDF/B are presented and discussed. The application of decay data in a wide variety of nuclear-related activities is illustrated by a number of examples. Two items pointed up by the ENDF/B decay-data compilation effort are treated: the identification of deficiencies in the data; and the importance of a radioactive-nuclide metrology effort oriented toward supplying these needs in a systematic fashion. 3 figures, 2 tables

  8. Radioactive-nuclide decay data in science and technology

    International Nuclear Information System (INIS)

    Reich, C.W.; Helmer, R.G.

    1975-01-01

    The scope of ENDF/B has recently been expanded to include radioactive-nuclide decay data. In this paper, the content and organization of the decay data which are included in ENDF/B are presented and discussed. The application of decay data in a wide variety of nuclear-related activities is illustrated by a number of examples. Two items pointed up by the ENDF/B decay-data compilation effort are treated: the identification of deficiencies in the data; and the importance of a radioactive-nuclide metrology effort oriented toward supplying these needs in a systematic fashion. (3 figures, 1 table)

  9. Few-body hypernuclear constraints

    International Nuclear Information System (INIS)

    Gibson, B.F.

    1993-01-01

    Since the discovery of the first hyperfragment in a balloon flown emulsion stack some two score years ago, physicists have worked to understand how the addition of the strangeness degree of freedom alters the picture of nuclei and the baryon-baryon force. Because the Λ and Σ masses differ markedly from that of the proton and neutron, SU (3) symmetry is broken. How it is broken is a question of importance to the fundamental understanding of the baryon-baryon interaction. New dynamical symmetries, forbidden by the Pauli principle in conventional nuclei, appear. Three-body forces play a more significant role. A binding anomaly in A = 5 as well as a possible spin inversion between ground and excited states in A = 4 appear. Surprisingly narrow structure near the threshold for Σ production has been reported in the 4 He (K - , π - ) spectrum while no corresponding structure is observed in the companion 4 He(K - , π + ) spectrum; this has been interpreted as evidence for a Σ 4 He bound state. Finally, the reported observation of ΛΛ-hypernuclei, in particular ΛΛ 6 He, bears directly upon the possibilities for the prediction of a bound H particle--the S = -2 dibaryon. Although it is not feasible to invert the analysis and determine the interaction from the data on few-body systems, it is possible to utilize these data to constrain the models, provided one is careful. The author will explore briefly the constraints which the few-body data impose and the level of understanding that has been achieved

  10. Rare B Decays at BaBar

    Energy Technology Data Exchange (ETDEWEB)

    Datta, M

    2005-03-14

    The authors present recent results on rare B meson decays based on data taken by the BABAR detector at the PEP-II asymmetric e{sup +}e{sup -} collider. Included in this report are measurements of branching fractions and other quantities of interest for several hadronic, radiative, electroweak, and purely leptonic decays of B mesons.

  11. Probings through proton decay and n-n-bar oscillations

    International Nuclear Information System (INIS)

    Pati, J.C.; Strathdee, J.

    1980-11-01

    Violation of baryon, lepton and in general fermion number is central to the hypothesis of quark lepton unification in a gauge context. Three of its characteristic signatures are proton decay, n-n-bar oscillation and neutrinoless double β decay. In 1974 and 1975 it was shown that within maximal gauging the proton may decay via four alternative modes (i.e. proton → one or three leptons or anti-leptons) satisfying ΔF = -2, 0, -4 and -6, some of which may coexist; the deuteron may decay into pions and neutrinoless double β decay occur in the context of spontaneous gauge symmetry breaking. It is now observed that n-n-bar oscillations (which are related to deuteron decays into protons) can coexist with proton decay especially of ΔF = -4 variety (p → e + π 0 ) and both these processes may possess measurable strength so as to be amenable to forthcoming searches. We exhibit alternative routes for spontaneous breakdown of the maximal one-family symmetry SU(16) and show that the coexistence of alternative proton decay modes (even with n-n-bar oscillations) does not pose any conflict with cosmological generation of baryon excess. Spontaneous rather than explicit violation of B, L and F plays an essential role in the realization of these features. (author)

  12. Nucleon decay in a realistic SO(10) SUSY GUT

    International Nuclear Information System (INIS)

    Lucas, V.; Raby, S.

    1997-01-01

    In this paper, we calculate neutron and proton decay rates and branching ratios in a predictive SO(10) SUSY GUT which agrees well with low energy data. We show that the nucleon lifetimes are consistent with the experimental bounds. The nucleon decay rates are calculated using all one-loop chargino and gluino-dressed diagrams regardless of their chiral structure. We show that the four-fermion operator C jk (u R d jR )(d kL ν τL ), commonly neglected in previous nucleon decay calculations, not only contributes significantly to nucleon decay, but, for many values of the initial GUT parameters and for large tanβ, actually dominates the decay rate. As a consequence, we find that τ p /τ n is often substantially larger than the prediction obtained in small tanβ models. We also find that gluino-dressed diagrams, often neglected in nucleon decay calculations, contribute significantly to nucleon decay. In addition we find that the branching ratios obtained from this realistic SO(10) SUSY GUT differ significantly from the predictions obtained from open-quotes genericclose quotes SU(5) SUSY GUT close-quote s. Thus, nucleon decay branching ratios, when observed, can be used to test theories of fermion masses. copyright 1997 The American Physical Society

  13. Invisible Higgs boson decay with B→Kνν constraint

    International Nuclear Information System (INIS)

    Kim, C. S.; Park, Seong Chan; Wang Kai; Zhu Guohuai

    2010-01-01

    If the Higgs boson were the only particle within the LHC accessible range, precision measurement of the Higgs's properties would play a unique role in studying electroweak symmetry breaking as well as possible new physics. We try to use low energy experiments such as rare B decay to constrain a challenging decay mode of Higgs, in which a Higgs decays to a pair of light (≅1∼2 GeV) SM singlet S and becomes invisible. By using the current experimental bound of rare decay B→Kνν and computing the contribution of B→KSS to (the) B→K+Ee, we obtain an upper bound on the Higgs coupling to such light singlet. It is interesting that the partial width of the invisible decay mode h→SS by taking the upper bound value of coupling is at a comparable level with h→WW/ZZ or WW ( * ) decay modes, making the Higgs identifiable but with a different predicted decay branching ratio from [the] standard model Higgs decay. It will then have an impact on precision measurement of the Higgs's properties. We also study the implication for cosmology from such a light singlet and propose a solution to the potential problem.

  14. Probings through proton decay and n-anti n oscillations

    International Nuclear Information System (INIS)

    Pati, J.C.; Strathdee, J.

    1981-01-01

    Violation of baryon, lepton and in general fermion number is central to the hypothesis of quark-lepton unification in a gauge context. Three of its characteristic signatures are proton decay, n-anti n oscillation and neutrinoless double β decay. In 1974 and 1975 it was shown that within maximal gauging the proton may decay via four alternative modes (i.e. proton → one or three leptons or antileptons) satisfying ΔF = -2, 0, -4 and -6, some of which may coexist; the deuteron may decay into pions and neutrinoless double β decay occur in the context of spontaneous gauge symmetry breaking. It is now observed that n-anti n oscillations (which are related to deuteron decays into pions) can coexist with proton decay especially of ΔF= -4 variety (p → e + π 0 ) and both these processes may possess measurable strength so as to be amenable to forthcoming searches. We exhibit alternative routes for spontaneous breakdown of the maximal one-family symmetry SU(16) and show that the coexistence of alternative proton decay modes (even with n-anti n oscillations) does not pose any conflict with cosmological generation of baryon excess. Spontaneous rather than explicit violation of B, L and F plays an essential role in the realization of these features. (orig.)

  15. Pursuing supersymmetry in Z0 decays

    International Nuclear Information System (INIS)

    Ellis, J.; Zwirner, F.

    1990-01-01

    We use recent LEP and SLC data on Z 0 decays and anti pp collider limits on W ± , Z 0 and gluino production to constrain the parameters of the chargino-neutralino sector in the minimal supersymmetric extension of the standard model. We show that unsuccessful chargino and gluino scarches, the anti pp collider ratio R=σ W e /σ Z e , and measurements of the total Z 0 width, peak hadronic cross section and invisible Z 0 with provide important constraints. The most stringent present bounds on invisible Z 0 decays assume the standard model for hadronic final states, and are therefore not directly applicable to supersymmetric models, which may have additional visible Z 0 decay modes. Possible signatures for supersymmetry in future Z 0 measurements include excesses in the total Z 0 width or in the invisible Z 0 width, but the most promising signal would be an observable cross section for 'zen' events, in which all the visible Z 0 decay products are in one hemisphere. (orig.)

  16. Proton decay in grand unified theories

    International Nuclear Information System (INIS)

    Lucha, W.

    1984-01-01

    Interactions which violate the conservation of baryon and lepton number represent an intrinsic part of all grand unified theories (GUTs) of strong and electroweak interactions. These new interactions - predicted within the framework of GUTs - generate B and L violating four-fermion interactions via the exchange of superheavy particles which cannot be ascribed a well-defined baryon or lepton number. The effective coupling constant of these four-fermion interactions might be large enough to make the proton decay detectable by the present generation of experiments. In this review the basic concepts of conventional as well as supersymmetric GUTs relevant for proton decay are sketched. The baryon number violating sector of grand unified theories is discussed in more detail. Special emphasis is laid on the various selection rules arising as consequences of low-energy gauge invariance and supersymmetry for proton decay. These selection rules already determine the coarse pattern of the resulting decay modes and branching ratios without any reference to or detailed knowledge of the underlying grand unified theory. Finally the numerous theoretical predictions are summarized and confronted with experiment. (Author)

  17. Exclusive nonleptonic B→VV decays

    International Nuclear Information System (INIS)

    Barik, N.; Naimuddin, Sk.; Dash, P. C.; Kar, Susmita

    2009-01-01

    The exclusive two-body nonleptonic B→VV decays are investigated, within the factorization approximation, in the relativistic independent quark model based on a confining potential in the scalar-vector harmonic form. The branching ratios and the longitudinal polarization fraction (R L ) are calculated yielding the model predictions in agreement with experiment. Our predicted CP-odd fraction (R perpendicular ) for B→D*D (s) * decays are in general agreement with other model predictions and within the existing experimental limit.

  18. The beta decay of hyperons

    International Nuclear Information System (INIS)

    Bohm, A.; Garcia, A.; Instituto Politecnico Nacional, Mexico City. Escuela Superior de Fisica y Matematicas); Kielanowski, P.; Texas Univ., Austin; Instituto Politecnico Nacional, Mexico City. Centro de Investigacion y de Estudios Avanzados)

    1985-01-01

    This book is an introduction to the physics of the semileptonic decay of hyperons. After a general introduction and a description of the experimental results the Cabibbo theory is introduced for the theoretical description of these results. Then radiative and other corrections are discussed. Finally this decay is considered in the framework of broken SU(3). This book applies to graduate students and other ''non-specialists'' who want to get some insight into the physics of weak interactions. (HSI)

  19. The 49K beta decay

    International Nuclear Information System (INIS)

    Hansen, P.G.; Huck, A.; Klotz, G.; Knipper, A.; Miehe, C.; Walter, G.; Jonson, B.; Mattsson, S.; Ravn, H.L.; Kratz, K.L.

    1981-01-01

    The decay of 49 K has been studied through neutron and gamma spectroscopy techniques. The 49 K activity was formed by 600 MeV proton fragmentation reactions in a uranium carbide target. The observed β-strength, in addition to the general behaviour expected from the gross theory of β-decay, displays two resonances centered at about 6.5 MeV and 9.5 MeV in 49 Ca. This structure is discussed in simple shell-model terms. (orig.)

  20. $\\Upsilon$ production in Z Decays

    CERN Document Server

    Acciarri, M; Aguilar-Benítez, M; Ahlen, S P; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alverson, G; Alviggi, M G; Ambrosi, G; Anderhub, H; Andreev, V P; Angelescu, T; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Baksay, L; Banerjee, S; Banerjee, Sw; Banicz, K; Barczyk, A; Barillère, R; Barone, L; Bartalini, P; Baschirotto, A; Basile, M; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Bhattacharya, S; Biasini, M; Biland, A; Bilei, G M; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böck, R K; Böhm, A; Boldizsar, L; Borgia, B; Boucham, A; Bourilkov, D; Bourquin, Maurice; Boutigny, D; Braccini, S; Branson, J G; Brigljevic, V; Brock, I C; Buffini, A; Buijs, A; Burger, J D; Burger, W J; Busenitz, J K; Cai, X D; Campanelli, M; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Castellini, G; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada-Canales, M; Cesaroni, F; Chamizo-Llatas, M; Chang, Y H; Chaturvedi, U K; Chekanov, S V; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chen, M; Chiefari, G; Chien, C Y; Cifarelli, Luisa; Cindolo, F; Civinini, C; Clare, I; Clare, R; Cohn, H O; Coignet, G; Colijn, A P; Colino, N; Commichau, V; Costantini, S; Cotorobai, F; de la Cruz, B; Csilling, Akos; Dai, T S; D'Alessandro, R; De Asmundis, R; Degré, A; Deiters, K; Denes, P; De Notaristefani, F; DiBitonto, Daryl; Diemoz, M; Van Dierendonck, D N; Di Lodovico, F; Dionisi, C; Dittmar, Michael; Dominguez, A; Doria, A; Dorne, I; Dova, M T; Drago, E; Duchesneau, D; Duinker, P; Durán, I; Dutta, S; Easo, S; Efremenko, Yu V; El-Mamouni, H; Engler, A; Eppling, F J; Erné, F C; Ernenwein, J P; Extermann, Pierre; Fabre, M; Faccini, R; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, Marta; Fenyi, B; Ferguson, T; Ferroni, F; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Fisk, I; Forconi, G; Fredj, L; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gau, S S; Gentile, S; Gerald, J; Gheordanescu, N; Giagu, S; Goldfarb, S; Goldstein, J; Gong, Z F; Gougas, Andreas; Gratta, Giorgio; Grünewald, M W; Gupta, V K; Gurtu, A; Gutay, L J; Hartmann, B; Hasan, A; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Van Hoek, W C; Hofer, H; Hong, S J; Hoorani, H; Hou, S R; Hu, G; Innocente, Vincenzo; Jenkes, K; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Kasser, A; Khan, R A; Kamrad, D; Kamyshkov, Yu A; Kapustinsky, J S; Karyotakis, Yu; Kaur, M; Kienzle-Focacci, M N; Kim, D; Kim, D H; Kim, J K; Kim, S C; Kim, Y G; Kinnison, W W; Kirkby, A; Kirkby, D; Kirkby, Jasper; Kiss, D; Kittel, E W; Klimentov, A; König, A C; Kopp, A; Korolko, I; Koutsenko, V F; Krämer, R W; Krenz, W; Kunin, A; Ladrón de Guevara, P; Landi, G; Lapoint, C; Lassila-Perini, K M; Laurikainen, P; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Leggett, C; Le Goff, J M; Leiste, R; Leonardi, E; Levchenko, P M; Li Chuan; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lu, W; Lü, Y S; Lübelsmeyer, K; Luci, C; Luckey, D; Luminari, L; Lustermann, W; Ma Wen Gan; Maity, M; Majumder, G; Malgeri, L; Malinin, A; Maña, C; Mangeol, D J J; Mangla, S; Marchesini, P A; Marin, A; Martin, J P; Marzano, F; Massaro, G G G; McNally, D; Mele, S; Merola, L; Meschini, M; Metzger, W J; Von der Mey, M; Mi, Y; Mihul, A; Van Mil, A J W; Mirabelli, G; Mnich, J; Molnár, P; Monteleoni, B; Moore, R; Morganti, S; Moulik, T; Mount, R; Müller, S; Muheim, F; Muijs, A J M; Nahn, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Niessen, T; Nippe, A; Nisati, A; Nowak, H; Oh, Yu D; Opitz, H; Organtini, G; Ostonen, R; Palomares, C; Pandoulas, D; Paoletti, S; Paolucci, P; Park, H K; Park, I H; Pascale, G; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Peach, D; Pei, Y J; Pensotti, S; Perret-Gallix, D; Petersen, B; Petrak, S; Pevsner, A; Piccolo, D; Pieri, M; Pinto, J C; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Postema, H; Produit, N; Prokofev, D; Prokofiev, D O; Rahal-Callot, G; Raja, N; Rancoita, P G; Rattaggi, M; Raven, G; Razis, P A; Read, K; Ren, D; Rescigno, M; Reucroft, S; Van Rhee, T; Riemann, S; Riles, K; Robohm, A; Rodin, J; Roe, B P; Romero, L; Rosier-Lees, S; Rosselet, P; Van Rossum, W; Roth, S; Rubio, Juan Antonio; Ruschmeier, D; Rykaczewski, H; Salicio, J; Sánchez, E; Sanders, M P; Sarakinos, M E; Sarkar, S; Sassowsky, M; Sauvage, G; Schäfer, C; Shchegelskii, V; Schmidt-Kärst, S; Schmitz, D; Schmitz, P; Schneegans, M; Scholz, N; Schopper, Herwig Franz; Schotanus, D J; Schwenke, J; Schwering, G; Sciacca, C; Sciarrino, D; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shukla, J; Shumilov, E; Shvorob, A V; Siedenburg, T; Son, D; Sopczak, André; Soulimov, V; Smith, B; Spillantini, P; Steuer, M; Stickland, D P; Stone, H; Stoyanov, B; Strässner, A; Strauch, K; Sudhakar, K; Sultanov, G G; Sun, L Z; Susinno, G F; Suter, H; Swain, J D; Tang, X W; Tauscher, Ludwig; Taylor, L; Ting, Samuel C C; Ting, S M; Tonutti, M; Tonwar, S C; Tóth, J; Tully, C; Tuchscherer, H; Tung, K L; Uchida, Y; Ulbricht, J; Uwer, U; Valente, E; Van de Walle, R T; Vesztergombi, G; Vetlitskii, I; Viertel, Gert M; Vivargent, M; Völkert, R; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Vorvolakos, A; Wadhwa, M; Wallraff, W; Wang, J C; Wang, X L; Wang, Z M; Weber, A; Wittgenstein, F; Wu, S X; Wynhoff, S; Xu, J; Xu, Z Z; Yang, B Z; Yang, C G; Yao, X Y; Ye, J B; Yeh, S C; You, J M; Zalite, A; Zalite, Yu; Zemp, P; Zeng, Y; Zhang, Z; Zhang, Z P; Zhou, B; Zhou, Y; Zhu, G Y; Zhu, R Y; Zichichi, Antonino; Ziegler, F

    1997-01-01

    We have searched for evidence of Upsilon production in 3.5 million hadronic Z decays collected by the L3 detector at LEP in 1991-1995. No signals are observed for the decay chain Z -> Upsilon X; Upsilon -> l+l- (l= e, mu), therefore upper limits at the 95% confidence level are set on the following Z branching fractions: BR (Z -> Upsilon(1S) X) Upsilon(2S) X) Upsilon(3S) X) < 9.4 x 10**-5.

  1. Weak decays of doubly heavy baryons. SU(3) analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei; Xing, Zhi-Peng; Xu, Ji [Shanghai Jiao Tong University, INPAC, Shanghai Key Laboratory for Particle Physics and Cosmology, School of Physics and Astronomy, Shanghai (China)

    2017-11-15

    Motivated by the recent LHCb observation of doubly charmed baryon Ξ{sub cc}{sup ++} in the Λ{sub c}{sup +}K{sup -}π{sup +}π{sup +} final state, we analyze the weak decays of doubly heavy baryons Ξ{sub cc}, Ω{sub cc}, Ξ{sub bc}, Ω{sub bc}, Ξ{sub bb} and Ω{sub bb} under the flavor SU(3) symmetry. The decay amplitudes for various semileptonic and nonleptonic decays are parametrized in terms of a few SU(3) irreducible amplitudes. We find a number of relations or sum rules between decay widths and CP asymmetries, which can be examined in future measurements at experimental facilities like LHC, Belle II and CEPC. Moreover, once a few decay branching fractions have been measured in the future, some of these relations may provide hints for exploration of new decay modes. (orig.)

  2. Introductory remarks on double beta decay and nuclear physics

    International Nuclear Information System (INIS)

    Rosen, S.P.

    1986-01-01

    The particle physics aspects of double beta decay and the theory of the phenomenon are briefly reviewed. The distinction between Dirac and Majorana neutrinos is drawn by comparing the neutrino that accompanies a negatively charged lepton in some hadronic decay process with that which accompanies a positively charged lepton in some other decay process. Two modes of double beta decay are examined - one emitting two neutrinos and the other emitting no neutrinos. What can be learned from the existing data on double beta decay is considered, de-emphasizing the question of bounds on neutrino mass and concentrating on the properties of the phenomenon itself. Possible future experiments are anticipated. 16 refs

  3. SU(6), baryonic decays of B-mesons and CP

    International Nuclear Information System (INIS)

    Wu, D.

    1990-01-01

    In this paper the four fermion weak decay Hamiltonian is expressed in terms of quark-antiquark creation operators with specific spin orientations. Then the SU(6) symmetry of the strong interactions among light quarks is imposed to find 8 invariant decay amplitudes for two body charmful baryonic decays of the B-mesons, 3 S-waves, 4 P- waves and 1 D-wave. Λ c branching ratio and some exclusive branching ratios are calculated based on the assumption of two body dominance in baryonic decay modes. Results on two body mesonic decays are also given. Relation between the SU(6) scheme and the quark diagram scheme is discussed

  4. Exclusive B Decays to Charmonium Final States

    Energy Technology Data Exchange (ETDEWEB)

    Barrera, Barbara

    2000-10-13

    We report on exclusive decays of B mesons into final states containing charmonium using data collected with the BABAR detector at the PEP-II storage rings. The charmonium states considered here are J/{psi}, {psi}(2S), and {chi}{sub c1}. Branching fractions for several exclusive final states, a measurement of the decay amplitudes for the B{sup 0} {yields} J/{psi} K* decay, and measurements of the B{sup 0} and B{sup +} masses are presented. All of the results we present here are preliminary.

  5. New puzzles in nonleptonic B and D decays

    International Nuclear Information System (INIS)

    Lipkin, H.J.

    1997-01-01

    Exclusive charged B decays show an unexplained enhancement in low-lying channels which must be reversed in other channels to equalise charged and neutral lifetimes. One suggested explanation involves decay modes with excited mesons like the a 1 . The anomalous behavior of decay modes of D and B mesons into final states containing the η and η'' mesons is discussed

  6. Similarity Decay of Enstrophy in an Electron Fluid

    International Nuclear Information System (INIS)

    Rodgers, D. J.; Matthaeus, W. H.; Mitchell, T. B.; Montgomery, D. C.

    2010-01-01

    A similarity decay law is proposed for enstrophy of a one-signed-vorticity fluid in a circular free-slip domain. It excludes the metastable equilibrium enstrophy which cannot drive turbulence, and approaches Batchelor's t -2 law for strong turbulence. Measurements of the decay of a turbulent electron fluid agree well with the predictions of the decay law for a variety of initial conditions.

  7. Beta decay of /sup 39/Cl

    International Nuclear Information System (INIS)

    Wang, G.; Warburton, E.K.; Alburger, D.E.

    1987-01-01

    The β decay of /sup 39/Cl, produced in the /sup 37/Cl(t,p)/sup 39/Cl reaction at E/sub t/ = 3.1 MeV, has been investigated with a Ge-NaI(Tl) Compton-suppression γ-ray spectrometer. Nineteen γ-ray transitions were observed, including 10 previously known. Precision energy measurements were carried out on six of the strongest lines. In the proposed decay scheme a weak new β-ray branch is established to the 2950-keV level of /sup 39/Ar, and the populations of /sup 39/Ar levels at 2093 and 2433 keV are accounted for by γ-ray decays from higher excited states. Spin-parity assignments are given

  8. Rare kaon decay: challenges and perspectives

    CERN Document Server

    D'Ambrosio, Giancarlo

    2015-01-01

    I review rare kaon decays. I introduce the flavor problem and p ossible solutions. Very rare kaon decays like K → π ν ̄ ν are very important to this purpose but also K → π l + l − . A new interesting channel is K → π π ee . Chiral dynamics is important to disentangle short distanc e effects. We discuss also the decays K 0 → μ + μ − , which have received recently some attention due to the measurement by LHCB.therefore we will study also K L → π 0 e + e − , K + → π + π 0 γ , K + → π + π 0 e + e − and related channels

  9. Kaon decay experiments at J-PARC

    International Nuclear Information System (INIS)

    Nanjo, Hajime

    2015-01-01

    Three kaon-decay experiments, E14 (KOTO), E36, and E06 (TREK), are being performed or planned in the Hadron Experimental Facility of J-PARC. The J-PARC accelerator provides 30-GeV intense proton beam with a slow-extraction method, which is one of the key points to achieve the physics goals for the experiments. In this article, the features of the kaon decay as a tool to explore new physics beyond the Standard Model are explained. The J-PARC accelerator and the Hadron Experimental Facility are briefly described. The three kaon-decay experiments are introduced, all of which are sensitive to the new physics beyond the Standard Model. (author)

  10. Nuclear aspects of double-beta decay

    International Nuclear Information System (INIS)

    Stoica, S.; Paun, V.

    2002-01-01

    Calculations of the neutrinoless double-beta decay (0νββ) matrix elements are performed with the second quasi random phase approximation (SQRPA) method for several nuclei. The results display a weak dependence on the single particle basis used and the Ikeda sum rule is fulfilled with good accuracy. Comparing our calculations with similar ones performed with other QRPA-based methods we estimate the accuracy of these methods in the prediction of the (0νββ) decay matrix elements and neutrino mass parameter, which is settled to about 50% from their calculated values. Taking the most recent experimental limits for the neutrinoless double beta decay half-lives, we also deduced new limits for the neutrino mass parameter. (authors)

  11. Teleportation via decay

    Indian Academy of Sciences (India)

    therefore normally plays a negative role in quantum information processing [1]. ... of a decay be used in a fruitful way for quantum information process- ing? ..... The model independent portions of the analysis of communication through a noisy.

  12. RARE KAON DECAYS

    International Nuclear Information System (INIS)

    LITTENBERG, L.

    2005-01-01

    Lepton flavor violation (LFV) experiments have probed sensitivities corresponding to mass scales of well over 100 TeV, making life difficult for models predicting accessible LFV in kaon decay and discouraging new dedicated experiments of this type

  13. Wood decay and the cleanup crew

    Science.gov (United States)

    Kevin T. Smith; Jessie A. Glaeser

    2017-01-01

    Arborists are encouraged to recognize the wood-decay process as an important factor in tree health and public safety. Technical experts who develop training materials to recognize wood-decay processes in living trees are frequently forest pathologists. Much of the history of forest pathology was to support production of sound, high-quality timber. That heritage is...

  14. Using correlation functions as free decays

    DEFF Research Database (Denmark)

    Brincker, Rune; Amador, Sandro; Juul, Martin

    It is a general assumption in OMA that correlation functions are free decays. In multiple input OMA this assumption also implies that any column in the correlation function matrix is to be considered as multiple output free decays. This assumption is discussed in this paper together with issues...... concerning estimation and application of correlations functions in OMA....

  15. Review of meson resonance radiative decays

    International Nuclear Information System (INIS)

    Thorndike, E.H.

    1977-01-01

    The radiative decays of meson resonances can be studied by three different approaches, it is noted. These are the meson-exchange, Primakoff effect, and the production of the desired resonance and subsequent observation of its decay. These approaches are criticized and examples of them are reviewed. Mass distributions are shown and branching ratios discussed. 21 references

  16. Reduction of precursor decay anomaly in single crystal lithium fluoride

    Science.gov (United States)

    Sano, Yukio

    2000-08-01

    The purpose of this study is to reveal that the precursor decay anomaly in single crystal lithium fluoride is reduced by Sano's decay curve [Y. Sano, J. Appl. Phys. 85, 7616 (1999)], which is much smaller in slope than Asay's decay curve [J. R. Asay, G. R. Fowles, G. E. Duvall, M. H. Miles, and R. F. Tinder, J. Appl. Phys. 43, 2132 (1972)]. To this end, strain, particle, velocity, and stress in a precursor and near the leading edge of the follower changing with time along Sano's decay curve are first analyzed quantitatively. The analysis verified the existence of degenerate contraction waves I and II and a subrarefaction wave R', and the decay process [Y. Sano, J. Appl. Phys. 77, 3746 (1995)] caused in sequence by evolving followers C, I, II, R', Rb. Next, inequalities relating decay rates qualitatively to plastic strain rates at the leading edge of the follower, which are derived using the properties of the followers, are incorporated into the analysis. Calculation results showed that the plastic strain rates were reduced by low decay rates. This indicates that the precursor decay anomaly might be greatly reduced by Sano's decay curve.

  17. The π+-emission puzzle in 4 over Lambda He decay

    International Nuclear Information System (INIS)

    Gibson, B.F.; Timmermans, R.

    1997-10-01

    The observed π + emission from the weak decay of 4 over Λ He has long been an intriguing puzzle. Experimentally, the π + to π - ratio for 4 over Λ He decay is about 5%. Because mesonic decay modes of the free Λ (→ p + π - , n + π 0 ) produce no π + s, more complicated mechanisms must be responsible for the π + decay of 4 over Λ He. Dalitz and von Hippel explored two-body decay processes of the type: (1) Λ → π 0 + n decay followed by a π 0 + p → π + + n charge-exchange reaction, and (2) Σ + → π + + n decay following a Λ + p → Σ + + n conversion. They concluded that neither process could account for even a 1% π + + n decay as a p-wave process ruled out the promising explanation coming from von Hippel's calculations, which had found that s-wave Σ + decay might yield a sufficiently high rate. Cieply and Gal re-examined the charge-exchange contribution and concluded that, although up-to-date input parameters yield a 1.2% branching ratio, the charge-exchange mechanism cannot account for the experimental value of about 5%

  18. Method and apparatus for induced nuclear beta decay

    International Nuclear Information System (INIS)

    Reiss, H.

    1986-01-01

    This invention relates to a method and apparatus for inducing beta decay transition that are normally inhibited by angular momentum or parity considerations. According to one aspect of this invention a method of inducing nuclear beta decay transition comprises providing a medium which includes atomic nuclei that have forbidden beta decay transition in which the initial and final nuclear states do not have the same intrinsic parity or have total angular momenta which differ by more than one quantum unit of angular momentum, and applying to the medium an electromagnetic field which has an intensity sufficient to provide the angular momentum or intrinsic parity necessary to overcome the forbiddenness of the beta decay transition of the atomic nuclei, thereby to induce the beta decay transitions. According to another aspect of this invention an apparatus for inducing beta decay transition comprises a medium which includes atomic nuclei that have forbidden beta decay transitions in which the initial and final nuclear states do not have the same intrinsic parity or have total angular momenta which differ by more than one quantum unit of angular momentum, field producing means for producing an electromagnetic field in the medium and means for energising the field producing means to establish the field at an intensity sufficient to provide the angular momentum or intrinsic parity necessary to overcome the forbiddenness of the beta decay transitions of the atomic nuclei. The energy released in these induced nuclear transition is useful for the controlled production of power. The induced beta dacay transitions are also useful to reduce the halflives of long-lived fission product wastes from conventional nuclear fission power plants

  19. Decay /sup 133/Ba

    Energy Technology Data Exchange (ETDEWEB)

    Singh, K; Hasiza, M L; Grewal, B S; Sahota, H S

    1982-07-01

    The relative gamma ray intensities of transitions in the decay of /sup 133/Ba have been measured using an intrinsic Ge detector. The electron capture branching ratios have been determined for 81, 161, 384 and 437 keV levels. The attenuation effect of long half-life of 81 keV levels has been studied in solid and liquid media. The electron capture decay has been investigated by changing the concentration of ethylene-diamine-tetraacetic acid (EDTA) environment. The 5/2/sup +/ yields 5/2/sup +/ 79.67 keV transition has an E0 to E2 intensity qsub(k)sup(2) <= 0.31. 10 refs., 4 figures.

  20. Decay uncovered in nonverbal short-term memory.

    Science.gov (United States)

    Mercer, Tom; McKeown, Denis

    2014-02-01

    Decay theory posits that memory traces gradually fade away over the passage of time unless they are actively rehearsed. Much recent work exploring verbal short-term memory has challenged this theory, but there does appear to be evidence for trace decay in nonverbal auditory short-term memory. Numerous discrimination studies have reported a performance decline as the interval separating two tones is increased, consistent with a decay process. However, most of this tone comparison research can be explained in other ways, without reference to decay, and these alternative accounts were tested in the present study. In Experiment 1, signals were employed toward the end of extended retention intervals to ensure that listeners were alert to the presence and frequency content of the memoranda. In Experiment 2, a mask stimulus was employed in an attempt to distinguish between a highly detailed sensory trace and a longer-lasting short-term memory, and the distinctiveness of the stimuli was varied. Despite these precautions, slow-acting trace decay was observed. It therefore appears that the mere passage of time can lead to forgetting in some forms of short-term memory.

  1. Charmless $B\\rightarrow VV$ decays at LHCb

    CERN Document Server

    Álvarez Cartelle, P

    2013-01-01

    $B^0_s$ meson decays into non--charmonium vector pairs are of particular interest to search for indirect $CP$ violation. The analyses of two specific decays are presented here, $B_s^0 \\rightarrow \\phi \\phi$ and $B_s^0 \\rightarrow K^{*0} \\bar{K}^{*0}$. These studies have been performed using, respectively, $1fb^{-1}$ and $35pb^{-1}$ of data collected by LHCb in $pp$ collisions at a centre--of--mass energy of 7 TeV. In $B_s^0 \\rightarrow \\phi \\phi$ decay, the $CP$--violating phase arising in the interference between $B_s^0$--$\\bar{B}_s^0$ mixing and the $b\\rightarrow s\\bar{s}s$ penguin decay has been determined to be in the interval $[-2.46,-0.76]$ rad at 68% confidence level. The first observation of $B_s^0 \\rightarrow K^{*0} \\bar{K}^{*0}$ decay is also reported. The branching fraction and the $CP$--averaged $K^{*0}$ longitudinal polarization fraction are measured to be $\\mathcal{B}(B_s^0 \\rightarrow K^{*0} \\bar{K}^{*0})$ = (2.81 $\\pm$ 0.46(stat.) $\\pm$ 0.45(syst.) $\\pm$ 0.34($f_s/f_d$))$\\times 10^{-5}...

  2. Study on diverse passive decay heat removal approach

    International Nuclear Information System (INIS)

    Lin Qian; Si Shengyi

    2012-01-01

    One of the most important principles for nuclear safety is the decay heat removal in accidents. Passive decay heat removal systems are extremely helpful to enhance the safety. In currently design of many advanced nuclear reactors, kinds of passive systems are proposed or developed, such as the passive residual heat removal system, passive injection system, passive containment cooling system. These systems provide entire passive heat removal paths from core to ultimate heat sink. Various kinds of passive systems for decay heat removal are summarized; their common features or differences on heat removal paths and design principle are analyzed. It is found that, these passive decay heat removal paths are similarly common on and connected by several basic heat transfer modes and steps. By the combinations or connections of basic modes and steps, new passive decay heat removal approach or diverse system can be proposed. (authors)

  3. Electrons and kaons in charmed particle decays

    International Nuclear Information System (INIS)

    Feller, J.M.

    1979-05-01

    Inclusive studies of the electron content, kaon content, and associated electron-kaon content of the decays of D mesons and other charmed particles produced in electron-positron annihilation are presented. At the psi(3772) resonance the following inclusive branching ratios for D meson decays to charged kaons were measured. Also at the psi(3772) resonance the average semileptonic branching ratio for D 0 and D + decays to electrons has been measured to be .076 +- .028. The average semileptonic branching ratio of charmed particles produced in e + e - annihilation at center-of-mass energies from 3.9 to 7.4 GeV is found to be equal within errors to that of the D's. At all energies the electron momentum spectra are consistent with a combination of the decays D → Ke nu and D → K*e nu. 84 references

  4. Beta decay of highly charged ions

    International Nuclear Information System (INIS)

    Litvinov, Yuri A; Bosch, Fritz

    2011-01-01

    Beta decay of highly charged ions has attracted much attention in recent years. An obvious motivation for this research is that stellar nucleosynthesis proceeds at high temperatures where the involved atoms are highly ionized. Another important reason is addressing decays of well-defined quantum-mechanical systems, such as one-electron ions where all interactions with other electrons are excluded. The largest modifications of nuclear half-lives with respect to neutral atoms have been observed in beta decay of highly charged ions. These studies can be performed solely at ion storage rings and ion traps, because there high atomic charge states can be preserved for extended periods of time (up to several hours). Currently, all experimental results available in this field originate from experiments at the heavy-ion complex GSI in Darmstadt. There, the fragment separator facility FRS allows the production and separation of exotic, highly charged nuclides, which can then be stored and investigated in the storage ring facility ESR. In this review, we present and discuss in particular two-body beta decays, namely bound-state beta decay and orbital electron capture. Although we focus on experiments conducted at GSI, we will also attempt to provide general requirements common to any other experiment in this context. Finally, we address challenging but not yet performed experiments and we give prospects for the new radioactive beam facilities, such as FAIR in Darmstadt, IMP in Lanzhou and RIKEN in Wako.

  5. Parametric Decay during HHFW on NSTX

    International Nuclear Information System (INIS)

    Wilson, J.R.; Bernabei, S.; Biewer, T.; Diem, S.; Hosea, J.; LeBlanc, B.; Phillips, C.K.; Ryan, P.; Swain, D.W.

    2005-01-01

    High Harmonic Fast Wave (HHFW) heating experiments on NSTX have been observed to be accompanied by significant edge ion heating (T i >> T e ). This heating is found to be anisotropic with T perp > T par . Simultaneously, coherent oscillations have been detected with an edge Langmuir probe. The oscillations are consistent with parametric decay of the incident fast wave (ω > 13ω ci ) into ion Bernstein waves and an unobserved ion-cyclotron quasi-mode. The observation of anisotropic heating is consistent with Bernstein wave damping, and the Bernstein waves should completely damp in the plasma periphery as they propagate toward a cyclotron harmonic resonance. The number of daughter waves is found to increase with rf power, and to increase as the incident wave's toroidal wavelength increases. The frequencies of the daughter wave are separated by the edge ion cyclotron frequency. Theoretical calculations of the threshold for this decay in uniform plasma indicate an extremely small value of incident power should be required to drive the instability. While such decays are commonly observed at lower harmonics in conventional ICRF heating scenarios, they usually do not involve the loss of significant wave power from the pump wave. On NSTX an estimate of the power loss can be found by calculating the minimum power required to support the edge ion heating (presumed to come from the decay Bernstein wave). This calculation indicates at least 20-30% of the incident rf power ends up as decay waves

  6. Very rare, exclusive, hadronic decays in QCD factorization

    International Nuclear Information System (INIS)

    König, Matthias

    2016-01-01

    We study exclusive hadronic decays of the electroweak bosons Z, W and h in the framework of QCD factorization. We show that the theory uncertainties in these channels are remarkably small compared to past applications of the QCD factorization framework. While the branching ratios are small, many of the modes are accessible at future colliders. The Higgs decays exhibit interesting dependences on the couplings due to the interferences of different diagram topologies, making the h → Vγ decays possible probes of the quark Yukawa couplings and the h → VZ decays probes of the coupling between the Higgs boson, a photon and a Z-boson.

  7. Test of right-handed currents in baryon semileptonic decays

    International Nuclear Information System (INIS)

    Garcia, A.; Huerta, R.; Maya, M.; Perez Marcial, R.

    1985-01-01

    The effect of a right-handed boson on baryon semileptonic decay is considered. The analysis of polarized and unpolarized decays is carried out and it is shown that the best place to look for a right-handed current (RHC) signature is in polarized baryon decay. However, our results are useful for high statistics experiments. In order to see the contribution of the right-handed currents in the case of unpolarized hyperon decay, the Cabibbo theory should be assumed. (orig.)

  8. Direct vs statistical decay of nuclear giant multipole resonances

    International Nuclear Information System (INIS)

    Hussein, M.S.

    1986-07-01

    A theoretical framework for the description of the decay of giant multipole resonances is developed. Besides the direct decay, both the pre-equilibrium and statistical (compound) decays are taken into account in a consistent way. It is shown that the statistical decay of the GR is not necessarily correctly described by the Hauser-Feshbach theory owing to the presence of a mixing parameter, which measures the degree of fragmentation. Applications are made to several cases. (Author) [pt

  9. Direct vs statistical decay of nuclear giant multipole resonances

    International Nuclear Information System (INIS)

    Dias, H.; Hussein, M.S.; Carlson, B.V.; Merchant, A.C.; Adhikari, S.K.

    1986-01-01

    A theoretical framework for the description of the decay of giant multipole resonances id developed. Besides the direct decay, both the pre-equilibrium and statistical (compound) decays are taken into account in a consistent way. It is shown that the statistical decay of the giant resonance is not necessarily described by the Hauser-Feshbach theory owing to the presence of a mixing parameter, which measures the degree of fragmentation. Applications are made to several cases. (Author) [pt

  10. Quantum Zeno effect for exponentially decaying systems

    International Nuclear Information System (INIS)

    Koshino, Kazuki; Shimizu, Akira

    2004-01-01

    The quantum Zeno effect - suppression of decay by frequent measurements - was believed to occur only when the response of the detector is so quick that the initial tiny deviation from the exponential decay law is detectable. However, we show that it can occur even for exactly exponentially decaying systems, for which this condition is never satisfied, by considering a realistic case where the detector has a finite energy band of detection. The conventional theories correspond to the limit of an infinite bandwidth. This implies that the Zeno effect occurs more widely than expected thus far

  11. Review of modern double beta decay experiments

    Science.gov (United States)

    Barabash, A. S.

    2015-10-01

    The review of modern experiments on search and studying of double beta decay processes is done. Results of the most sensitive current experiments are discussed. The main attention is paid to EXO-200, KamLAND-Zen, GERDA-I and CUORE-0 experiments. Modern values of T1/2(2ν) and best present limits on neutrinoless double beta decay and double beta decay with Majoron emission are presented. Conservative limits on effective mass of a Majorana neutrino ( at the level of ˜ 0.01-0.1 eV are discussed.

  12. Parametric decay below the upper hybrid frequency

    Energy Technology Data Exchange (ETDEWEB)

    Albers, E; Krause, K; Schlueter, H [Bochum Univ. (Germany, F.R.). Inst. fuer Experimentalphysik 2

    1977-03-21

    Parametric decay of the upper hybrid mode is observed between the electron cyclotron frequency and its first two harmonics. The decay products are identified as electron Bernstein and ion acoustic mode. The diagnostic results confirm the relevant dispersion relations.

  13. Present Status of Inclusive Rare $B$ Decays

    CERN Document Server

    Hurth, Tobias

    2003-01-01

    We give a status report on inclusive rare B decays, highlighting recent developments and open problems. We focus on the decay modes $B \\to X_{s,d} \\gamma$, $ B \\to X_s \\ell^+\\ell^-$ and $B \\to X_s \

  14. Towards a quantitative description of hadronic weak decays

    International Nuclear Information System (INIS)

    Bigi, I.I.Y.

    1981-01-01

    We develop a formalism for describing hadronic weak annihilation decays in analogy to the treatment of deep inelastic lepton-nucleon scattering: we write down evolution equations for colour singlet and octet (Qanti q) systems inside mesons of increasing mass. Using D decays as input we can predict weak annihilation decay rates of heavier mesons in a semiquantitative fashion despite our ignorance on bound-state dynamics. (orig.)

  15. Inclusive spectra of hadrons in B-meson decays

    International Nuclear Information System (INIS)

    Dobrovol'skaya, A.V.; Ter-Martirosyan, K.A.; Zoller, V.R.

    1989-01-01

    The inclusive spectra of hadrons (mainly pions) produced in the semileptonic and nonleptonic decays of B-mesons are calculated. Parameters of spectra for different types of hard qq-bar-strings, appearing in the B-meson decays, are determined using the data on e+e-annihilation. Numerical results for B-meson decay induced by both b→b and b→u transitions are presented. 10 refs.; 5 figs

  16. Strangeness-changing vector currents in τ-lepton decays

    International Nuclear Information System (INIS)

    Bednyakov, V.A.; Osipov, A.A.

    1992-01-01

    The Cabibbo suppressed τ-lepton decays into a kaon and a non-strange pseudoscalar meson have been investigated in the U(3)-version of the superconducting quark model with allowance for ΦA-mixing. The total and differential widths of four τ-lepton decays were obtained. The number of these decays per year at the c-τ-factory was calculated. 6 refs.; 4 figs.; 2 tabs

  17. Beta-decay of 56Cu

    International Nuclear Information System (INIS)

    Ramdhane, M.; Baumann, P.; Knipper, A.; Walter, G.; Janas, Z.; Plochocki, A.; Liu, W.; Grawe, H.; Hu, Z.; Kirchner, R.; Klepper, O.; Roeckl, E.; Gorska, M.; Fujita, Y.; Brown, B.A.

    1998-02-01

    By measuring positrons and β-delayed γ-rays emitted from mass-separated sources, the decay of 56 Cu(4 + ,T z =-1,T=1) to states in the doubly-magic nucleus 56 Ni was studied for the first time. The half-life of 56 Cu was measured to be 78(15) ms, and four β-delayed γ-rays were assigned to its decay. The resulting experimental data on Fermi and Gamow-Teller strength are compared with shell-model predictions. (orig.)

  18. β-decay of 37Ca

    International Nuclear Information System (INIS)

    Trinder, W.; Adelberger, E.G.; Keller, H.; Krumbholz, K.; Rykaczewski, K.

    1994-11-01

    The β-decay of 37 Ca has been studied. The half-life was remeasured with improved precision to be 181(1) ms, and β-delayed γ-rays were observed for the first time. The surprisingly high Γ γ /Γ p values for proton-unbound states in 37 K drastically reduce former discrepancies between the Gamow-Teller strength values B(GT) measured in the 37 Ga β-decay and those deduced from the 37 Cl(p, n) 37 Ar mirror reaction. (orig.)

  19. Study on diverse passive decay heat removal approach and principle

    International Nuclear Information System (INIS)

    Lin Qian; Si Shengyi

    2012-01-01

    Decay heat removal in post-accident is one of the most important aspects concerned in the reactor safety analysis. Passive decay heat removal approach is used to enhance nuclear safety. In advanced reactors, decay heat is removed by multiple passive heat removal paths through core to ultimate heat sink by passive residual heat removal system, passive injection system, passive containment cooling system and so on. Various passive decay heat removal approaches are summarized in this paper, the common features and differences of their heat removal paths are analyzed, and the design principle of passive systems for decay heat removal is discussed. It is found that. these decay heat removal paths is combined by some basic heat transfer processes, by the combination of these basic processes, diverse passive decay heat removal approach or system design scheme can be drawn. (authors)

  20. Simulation studies of the hypernuclear experiment at anti PANDA to optimize the production and detection rates of ΛΛ hypernuclei

    Energy Technology Data Exchange (ETDEWEB)

    Bleser, Sebastian; Martinez Rojo, Marta; Sanchez Lorente, Alicia; Steinen, Marcell [Helmholtz-Institut Mainz (Germany); Gerl, Juergen; Kojouharova, Jasmina; Kojouharov, Ivan [GSI, Darmstadt (Germany); Iazzi, Felice [Politecnico, Torino (Italy); INFN, Torino (Italy); Pochodzalla, Josef [Helmholtz-Institut Mainz (Germany); Inst. fuer Kernphysik, JGU Mainz (Germany); Rathmann, Torben [Inst. fuer Kernphysik, JGU Mainz (Germany); Collaboration: PANDA-Collaboration

    2015-07-01

    A key aspect of the anti PANDA experiment at the future FAIR facility is the production and spectroscopy of ΛΛ hypernuclei. The double hypernuclei are produced in a two-stage target system consisting of a primary in-beam filament to produce Ξ{sup -} hyperons which are stopped and converted into two lambda hyperons in a secondary external target. This device is composed of a sandwich structure of layers of absorber material and silicon strip detectors for the formation of ΛΛ hypernuclei and the detection of their charged decay pions. In particular the detection of these pions give a signature of a ΛΛ hypernuclei and tag the event. The high resolution γ spectroscopy of the excited hypernuclei is performed by an array of germanium detectors. This poster shows the simulation studies to optimize the setup concerning the production of the hypernuclei and the tracking of their decay pions. In addition the absorption of γ in the target material is taken into account. Furthermore the influence of background is studied since it might damage the germanium detectors and on the other hand is crucial to provide a good signal-to-noise ratio.

  1. Decay rates of quarkonia and potential models

    International Nuclear Information System (INIS)

    Rai, Ajay Kumar; Pandya, J N; Vinodkumar, P C

    2005-01-01

    The decay rates of cc-bar and b-barb mesons have been studied with contributions from different correction terms. The corrections based on hard processes involved in the decays are quantitatively studied in the framework of different phenomenological potential models

  2. Correlation of gravestone decay and air quality 1960-2010

    Science.gov (United States)

    Mooers, H. D.; Carlson, M. J.; Harrison, R. M.; Inkpen, R. J.; Loeffler, S.

    2017-03-01

    Evaluation of spatial and temporal variability in surface recession of lead-lettered Carrara marble gravestones provides a quantitative measure of acid flux to the stone surfaces and is closely related to local land use and air quality. Correlation of stone decay, land use, and air quality for the period after 1960 when reliable estimates of atmospheric pollution are available is evaluated. Gravestone decay and SO2 measurements are interpolated spatially using deterministic and geostatistical techniques. A general lack of spatial correlation was identified and therefore a land-use-based technique for correlation of stone decay and air quality is employed. Decadally averaged stone decay is highly correlated with land use averaged spatially over an optimum radius of ≈7 km even though air quality, determined by records from the UK monitoring network, is not highly correlated with gravestone decay. The relationships among stone decay, air-quality, and land use is complicated by the relatively low spatial density of both gravestone decay and air quality data and the fact that air quality data is available only as annual averages and therefore seasonal dependence cannot be evaluated. However, acid deposition calculated from gravestone decay suggests that the deposition efficiency of SO2 has increased appreciably since 1980 indicating an increase in the SO2 oxidation process possibly related to reactions with ammonia.

  3. Particle creation during vacuum decay

    International Nuclear Information System (INIS)

    Rubakov, V.A.

    1984-01-01

    The hamiltonian approach is developed with regard to the problem of particle creation during the tunneling process, leading to the decay of the false vacuum in quantum field theory. It is shown that, to the lowest order in (h/2π), the particle creation is described by the euclidean Schroedinger equation in an external field of a bounce. A technique for solving this equation is developed in an analogy to the Bogoliubov transformation technique, in the theory of particle creation in the presence of classical background fields. The technique is illustrated by two examples, namely, the particle creation during homogeneous vacuum decay and during the tunneling process leading to the materialization of the thin-wall bubble of a new vacuum in the metastable one. The curious phenomenon of intensive particle annihilation during vacuum decay is discussed and explicitly illustrated within the former example. The non-unitary extension of the Bogoliubov u, v transformations is described in the appendix. (orig.)

  4. Measurement of tau polarization in Z boson decays at ATLAS

    Energy Technology Data Exchange (ETDEWEB)

    Winter, Benedict; Davey, William; Dingfelder, Jochen [Physikalisches Institut, Universitaet Bonn (Germany)

    2016-07-01

    Decays of the Z boson in the Standard Model violate parity, leading to a net polarization of the decay products. Z boson decays to pairs of tau leptons provide a unique opportunity to measure the tau polarization by using the kinematics of the subsequent tau decays, hence testing the Standard Model predictions. They also provide a unique opportunity to pioneer experimental techniques that assess the tau helicity and may be used in searches for new particles and to study the properties of the Higgs boson. In this talk the status of the first measurement of the tau polarization in Z→ττ decays at a hadronic collider is presented. The analysis is based on the 20.3 fb{sup -1} collected by the ATLAS experiment at a center-of-mass energy of √(s) = 8 TeV. The tau polarization is measured in events in which one tau decays leptonically and the other decays hadronically by using the kinematics of the hadronic decay. A main focus is set on the determination of the systematic uncertainties and the limit setting procedure.

  5. Decay spectroscopy for nuclear astrophysics: β- and β-delayed proton decay

    Science.gov (United States)

    Trache, L.; Banu, A.; Hardy, J. C.; Iacob, V. E.; McCleskey, M.; Roeder, B. T.; Simmons, E.; Spiridon, A.; Tribble, R. E.; Saastamoinen, A.; Jokinen, A.; Äysto, J.; Davinson, T.; Lotay, G.; Woods, P. J.; Pollacco, E.

    2012-02-01

    In several radiative proton capture reactions important in novae and XRBs, the resonant parts play the capital role. We use decay spectroscopy techniques to find these resonances and study their properties. We have developed techniques to measure beta- and beta-delayed proton decay of sd-shell, proton-rich nuclei produced and separated with the MARS recoil spectrometer of Texas A&M University. The short-lived radioactive species are produced in-flight, separated, then slowed down (from about 40 MeV/u) and implanted in the middle of very thin Si detectors. This allows us to measure protons with energies as low as 200 keV from nuclei with lifetimes of 100 ms or less. At the same time we measure gamma-rays up to 8 MeV with high resolution HPGe detectors. We have studied the decay of 23Al, 27P, 31Cl, all important for understanding explosive H-burning in novae. The technique has shown a remarkable selectivity to beta-delayed charged-particle emission and works even at radioactive beam rates of a few pps. The states populated are resonances for the radiative proton capture reactions 22Na(p,γ)23Mg (crucial for the depletion of 22Na in novae), 26mAl(p,γ)27Si and 30P(p,γ)31S (bottleneck in novae and XRB burning), respectively. Lastly, results with a new detector that allowed us to measure down to about 80 keV proton energy are announced.

  6. Decay spectroscopy for nuclear astrophysics: β- and β-delayed proton decay

    International Nuclear Information System (INIS)

    Trache, L; Banu, A; Hardy, J C; Iacob, V E; McCleskey, M; Roeder, B T; Simmons, E; Spiridon, A; Tribble, R E; Saastamoinen, A; Jokinen, A; Äysto, J; Davinson, T; Lotay, G; Woods, P J; Pollacco, E

    2012-01-01

    In several radiative proton capture reactions important in novae and XRBs, the resonant parts play the capital role. We use decay spectroscopy techniques to find these resonances and study their properties. We have developed techniques to measure beta- and beta-delayed proton decay of sd-shell, proton-rich nuclei produced and separated with the MARS recoil spectrometer of Texas A and M University. The short-lived radioactive species are produced in-flight, separated, then slowed down (from about 40 MeV/u) and implanted in the middle of very thin Si detectors. This allows us to measure protons with energies as low as 200 keV from nuclei with lifetimes of 100 ms or less. At the same time we measure gamma-rays up to 8 MeV with high resolution HPGe detectors. We have studied the decay of 23 Al, 27 P, 31 Cl, all important for understanding explosive H-burning in novae. The technique has shown a remarkable selectivity to beta-delayed charged-particle emission and works even at radioactive beam rates of a few pps. The states populated are resonances for the radiative proton capture reactions 22 Na(p,γ) 23 Mg (crucial for the depletion of 22 Na in novae), 26m Al(p,γ) 27 Si and 30 P(p,γ) 31 S (bottleneck in novae and XRB burning), respectively. Lastly, results with a new detector that allowed us to measure down to about 80 keV proton energy are announced.

  7. Probing supersymmetry in rare B decays

    International Nuclear Information System (INIS)

    Hewett, J.L.

    1996-10-01

    We determine the ability of future experiments to observe supersymmetric contributions to the rare decays B → X s γ and B → X s l + l - . A global fit to the Wilson coefficients which contribute to these decays is performed from Monte Carlo generated data. This fit is then compared to supersymmetric predictions for several different patterns of the superpartner spectrum

  8. Top quark decays in extended models

    International Nuclear Information System (INIS)

    Gaitan, R.; Cabral-Rosetti, L.G.

    2011-01-01

    We evaluate the FCNC decays t → H 0 + c at tree-level and t → γ + c at one-loop level in the context of Alternative Left-Right symmetric Models (ALRM) with extra isosinglet heavy fermions; in the first case, FCNC decays occurs at tree-level and they are only suppressed by the mixing between ordinary top and charm quarks. (author)

  9. The lambda mechanism of the 0nbb-decay

    Science.gov (United States)

    Šimkovic, Fedor; Štefánik, Dušan; Dvornický, Rastislav

    2017-11-01

    The lambda mechanism (WL-WR exchange) of the neutrinoless double beta decay (0nbb-decay), which has origin in left-right symmetric model with right-handed gauge boson at TeV scale, is investigated. The revisited formalism of the 0nbb-decay, which includes higher order terms of nucleon current, is exploited. The corresponding nuclear matrix elements are calculated within quasiparticle random phase approximation with partial restoration of the isospin symmetry for nuclei of experimental interest. A possibility to distinguish between the conventional light neutrino mass (WL-WL exchange) and lambda mechanisms by observation of the 0nbb-decay in several nuclei is discussed. A qualitative comparison of effective lepton number violating couplings associated with these two mechanisms is performed. By making viable assumption about the seesaw type mixing of light and heavy neutrinos it is concluded that there is a dominance of the conventional light neutrino mass mechanism in the decay rate.

  10. Rare decays of the Higgs boson with the CMS detector

    OpenAIRE

    Marini, Andrea Carlo

    2018-01-01

    The CMS collaboration reports the latest update on the searches of invisible and rare decays of the Higgs boson. The searches for the standard model Higgs boson decaying into two muons, for the standard model Higgs boson decaying into $\\ell\\ell\\gamma$, and for invisible decay of the Higgs boson in the vector boson fusion production channel are presented.

  11. Flavor SU(3) in hadronic B decays

    International Nuclear Information System (INIS)

    Dighe, A.

    1998-11-01

    Here we shall outline a few methods that use the flavor SU(3) symmetry in the decays of B mesons to determine the angles of the unitarity triangle and to identify the decay modes which would display a significant CP violation. (author)

  12. Initial decay process of radicals induced in irradiated food

    International Nuclear Information System (INIS)

    Kaimori, Yoshihiko; Sakamoto, Yuki; Nakamura, Hideo; Ukai, Mitsuko; Kikuchi, Masahiro; Shimoyama, Yuhei; Kobayashi, Yasuhiko; Kameya, Hiromi

    2011-01-01

    In order to determine radial decay behaviors of γ-irradiated food, we analyzed radicals in the food using ESR. We detected the ESR signal of specimens just several minutes after irradiation. The singlet signal intensity at g=2.0, originated from organic free radicals was increased as followed by the increasing radiation dose. Singlet signal intensity that increased by γ-irradiation was decreased with time. The phenomena of decay of the ESR singlet signal showed two phase that are rapid decay and slow decay. It was suggested that those two phase decay is due to at least the two radical species. Also we concluded that after three hours of radiation treatment long life radical as ESR signal intensity was detected in irradiated specimen; black pepper, green coffee bean and ginseng, showed the same decay phenomena. But the signal intensity of irradiated black pepper was three times larger than that of irradiated green coffee bean and irradiated ginseng. (author)

  13. The Re-evaluation of 84Rb decay data

    International Nuclear Information System (INIS)

    Huang Xiaolong; Zhou Chunmei

    1996-01-01

    The 84 Rb is an important radionuclide and its decay data are fundamental data in nuclear applications. The decay data for 84 Rb were re-evaluated. The energies and intensities of γ rays and their internal conversion coefficients, energies and intensities of Auger electrons, conversion electrons and x-rays, were recommended. The decay scheme was also given. The balance of radiation rays intensities and energies was checked. (9 tabs., 2 figs.)

  14. Review of modern double beta decay experiments

    Energy Technology Data Exchange (ETDEWEB)

    Barabash, A. S., E-mail: barabash@itep.ru [Institute of Theoretical and Experimental Physics (NRC ”Kurchatov Institute”), B. Cheremushkinskaya 25, Moscow (Russian Federation)

    2015-10-28

    The review of modern experiments on search and studying of double beta decay processes is done. Results of the most sensitive current experiments are discussed. The main attention is paid to EXO-200, KamLAND-Zen, GERDA-I and CUORE-0 experiments. Modern values of T{sub 1/2}(2ν) and best present limits on neutrinoless double beta decay and double beta decay with Majoron emission are presented. Conservative limits on effective mass of a Majorana neutrino (〈m{sub ν}〉 < 0.46 eV) and a coupling constant of Majoron to neutrino (〈g{sub ee}〉 < 1.3 · 10{sup −5}) are obtained. Prospects of search for neutrinoless double beta decay in new experiments with sensitivity to 〈m{sub ν}〉 at the level of ∼ 0.01-0.1 eV are discussed.

  15. Decay and Snapback in Superconducting Accelerator Magnets

    CERN Document Server

    Haverkamp, M

    2003-01-01

    This thesis deals with the explanation and compensation of the effects 'decay' and 'snapback' in superconducting accelerator magnets, in particular in those used in the new Large Hardron Collider at CERN. During periods of constant magnet excitation, as for example during the injection of particles in the storage ring, the magnetic field in superconducting accelerator magnets shows a decay behavior. As soon as the particles are accelerated, the magnets are ramped, and the magnetic field 'snaps back' to the original hysteresis curve. Decay and snapback affect the beam in the machine and have tobe compensated precisely in order to avoid losses of particles. The research presented in this thesis is a step towards a better understanding of 'decay' and 'snapback' in superconducting particle accelerators. The thesis provides tools for the prediction and compensation of both effects in the magnets, and for the analysis of correlations between different magnet parameters.

  16. CP violation in B and D decays

    International Nuclear Information System (INIS)

    Bigi, I.I.

    1986-06-01

    Non-leptonic B decays offer the best opportunity to discover the violation of CP invariance outside the neutral K system. Employing the Standard Model one predicts - with reasonable confidence - CP asymmetries of up to 205 (or even more in some cases). The branching ratios for the individual exclusive modes of interest are not expected to exceed the 10 -3 level in most cases; the identification of such decays poses non-trivial problems. It is shown that by summing intelligently over appropriate classes of decays one can greatly enhance statistics without jeopardizing the signal. Data that contain 10 6 produced B mesons would allow meaningful searches for CP violation. It is noted that ''New Physics'' could lead to CP asymmetries in D 0 decays of order 1%. Due to higher branching ratios one can search for such effects in samples of 10 6 produced D mesons. 7 refs

  17. Determination of αs from Υ decays

    International Nuclear Information System (INIS)

    Bizzeti, A.

    1989-01-01

    The hadronic width of Υ(nS) is described in lowest order in QCD as the decay into three gluons. The partial decay width Γ 3g depends on the strong coupling constant to the third power and should thus allow a very accurate determination of α s . As all the partial decay widths of Υ involving the annihilation of the banti b system are proportional to the square of the wave function at the origin, in order to eliminate the dependence from the unknown wave function we need to form ratios of widths. The ratios Γ γ gg/Γ 3g and Γ μμ /Γ 3g can be determined experimentally, the first by counting the number of direct photons per hadronic event from Υ decays and the other by measuring the branching fraction B μμ , = Γ μμ /Γ tot . (orig./HSI)

  18. Hadronic B decays at LHCb

    International Nuclear Information System (INIS)

    Latham, T.E.

    2014-01-01

    We present recent results from the analysis of hadronic decays of B s 0 mesons at LHCb detector. The analyses use the data sample collected in 2011, which correspond to an integrated luminosity of 1.0 fb -1 . A large variety of different decays are being studied in order to probe for signs of physics beyond the Standard Model. The statistics available in the 2011 data sample already allow sophisticated analysis techniques, such as the Dalitz-plot analysis and the angular analysis to be employed

  19. Double beta decay: Comparison of theory to experiment

    International Nuclear Information System (INIS)

    Haxton, W.C.

    1992-01-01

    I review ββ decay in the standard model and as a test of Majorana neutrino masses and right-handed couplings. A summary is given of some of the nuclear physics issues involved in evaluating 2 ν and 0ν matrix elements. Dirac and pseudoDirac limits are discussed to illustrate how quantities constrained on 0ν ββ decay depend on the parameters of the mass matrix. Implications of 0ν ββ decay for models with 17 keV neutrinos, for models with massive Majorana neutrinos, and for Majorons are discussed. It is argued that a recent remeasurement of the total ββ decay rate of 126 Te is important in constraining (nonstandard) Majoron models

  20. Uncertainties in fission-product decay-heat calculations

    Energy Technology Data Exchange (ETDEWEB)

    Oyamatsu, K.; Ohta, H.; Miyazono, T.; Tasaka, K. [Nagoya Univ. (Japan)

    1997-03-01

    The present precision of the aggregate decay heat calculations is studied quantitatively for 50 fissioning systems. In this evaluation, nuclear data and their uncertainty data are taken from ENDF/B-VI nuclear data library and those which are not available in this library are supplemented by a theoretical consideration. An approximate method is proposed to simplify the evaluation of the uncertainties in the aggregate decay heat calculations so that we can point out easily nuclei which cause large uncertainties in the calculated decay heat values. In this paper, we attempt to clarify the justification of the approximation which was not very clear at the early stage of the study. We find that the aggregate decay heat uncertainties for minor actinides such as Am and Cm isotopes are 3-5 times as large as those for {sup 235}U and {sup 239}Pu. The recommended values by Atomic Energy Society of Japan (AESJ) were given for 3 major fissioning systems, {sup 235}U(t), {sup 239}Pu(t) and {sup 238}U(f). The present results are consistent with the AESJ values for these systems although the two evaluations used different nuclear data libraries and approximations. Therefore, the present results can also be considered to supplement the uncertainty values for the remaining 17 fissioning systems in JNDC2, which were not treated in the AESJ evaluation. Furthermore, we attempt to list nuclear data which cause large uncertainties in decay heat calculations for the future revision of decay and yield data libraries. (author)

  1. Aspects of radiative K{sup +}{sub e3} decays

    Energy Technology Data Exchange (ETDEWEB)

    Kubis, B. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Mueller, E.H. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); University of Edinburgh, School of Physics, Edinburgh (United Kingdom); Gasser, J.; Schmid, M. [Universitaet Bern, Institut fuer theoretische Physik, Bern (Switzerland)

    2007-04-15

    We re-investigate the radiative charged kaon decay K{sup {+-}}{yields}{pi}{sup 0}e{sup {+-}}{nu}{sub e}{gamma} [K{sub e3{gamma}}{sup {+-}}] in chiral perturbation theory, merging the chiral expansion with Low's theorem. We thoroughly analyze the precision of the predicted branching ratio relative to the non-radiative decay channel. Structure dependent terms and their impact on differential decay distributions are investigated in detail, and the possibility to see effects of the chiral anomaly in this decay channel is emphasized. (orig.)

  2. Radiative decays of vector mesons in the chiral bag model

    International Nuclear Information System (INIS)

    Tabachenko, A.N.

    1988-01-01

    A new model of radiative π-meson decays of vector mesons in the chiral bag model is proposed. The quark-π-meson interaction has the form of a pseudoscalar coupling and is located on the bag surface. The vector meson decay width depends on the quark masses, the π-meson decay constant, the radius of the bag, and the free parameter Z 2 , which specifies the disappearance of the bag during the decay. The obtained results for the omega- and p-decay widths are in satisfactory agreement with the experiment

  3. Compilations and evaluations of nuclear structure and decay data

    International Nuclear Information System (INIS)

    Lorenz, A.

    1977-03-01

    This is the second issue of a report series on published and to-be-published compilations and evaluations of nuclear structure and decay (NSD) data. This compilation of compilations and evaluations is designed to keep the nuclear scientific community informed of the availability of compiled or evaluated NSD data, and contains references to laboratory reports, journal articles and books containing selected compilations and evaluations. It excludes references to ''mass-chain'' evaluations normally published in the ''Nuclear Data Sheets'' and ''Nuclear Physics''. The material contained in this compilation is sorted according to eight subject categories: general compilations; basic isotopic properties; nuclear structure properties; nuclear decay processes; half-lives, energies and spectra; nuclear decay processes: gamma-rays; nuclear decay processes: fission products; nuclear decay processes: (others); atomic processes

  4. Detection of Higgs bosons decaying to bottom quarks

    International Nuclear Information System (INIS)

    Gilman, F.J.; Price, L.E.

    1986-11-01

    Several developments affecting the possibility of Higgs detection are discussed. These include the level of certainty about the t quark mass, Monte Carlo programs to generate both signal and background events, and separation and/or enhancement of heavy quark jets from jets due to light quarks or gluons, and the possibility that the neutral Higgs decay into bottom quarks might be the decay mode of choice for detecting the intermediate mass Higgs. Possible means of detection of an intermediate mass Higgs at the SSC, particularly if a prominent decay mode is to bottom quarks, are examined, using the PYTHIA Monte Carlo program to generate both signal and background events. For the signal, events were generated in which Higgs bosons are created in proton-proton collisions, with the Higgs decaying into bottom quarks. The presence of W or Z bosons, created in the same proton-proton collision, is used to enhance the likelihood of Higgs production and to reduce the potentially enormous background. It is found that the Higgs decay to bottom quarks, if important, would be more favorable for detection of the Higgs than decay to top quarks was found to be because of the smaller background. 3 refs., 4 figs

  5. Neutrinoless double β decay and effective field theory

    International Nuclear Information System (INIS)

    Prezeau, G.; Ramsey-Musolf, M.; Vogel, Petr

    2003-01-01

    We analyze neutrinoless double β decay (0νββ decay) mediated by heavy particles from the standpoint of effective field theory. We show how symmetries of the 0νββ-decay quark operators arising in a given particle physics model determine the form of the corresponding effective, hadronic operators. We classify the latter according to their symmetry transformation properties as well as the order at which they appear in a derivative expansion. We apply this framework to several particle physics models, including R-parity violating supersymmetry (RPV SUSY) and the left-right symmetric model (LRSM) with mixing and a right-handed Majorana neutrino. We show that, in general, the pion exchange contributions to 0νββ decay dominate over the short-range four-nucleon operators. This confirms previously published RPV SUSY results and allows us to derive new constraints on the masses in the LRSM. In particular, we show how a nonzero mixing angle ζ in the left-right symmetry model produces a new potentially dominant contribution to 0νββ decay that substantially modifies previous limits on the masses of the right-handed neutrino and boson stemming from constraints from 0νββ decay and vacuum stability requirements

  6. Conservation of basic monopoles in decay processes

    International Nuclear Information System (INIS)

    Barricelli, N.A.

    1983-01-01

    The conversation law of basic monpoles and other rules followed by these monopoles in the formation and decay processes of elementary particles are presented and discussed. A new interpretation of the distinction between rapid decay process (commonly ascribed to weak interactions) is proposed. (Auth.)

  7. Charged-particle multiplicities in B-meson decay

    International Nuclear Information System (INIS)

    Alam, M.S.; Csorna, S.E.; Fridman, A.; Hicks, R.G.; Panvini, R.S.; Andrews, D.; Avery, P.; Berkelman, K.; Cabenda, R.; Cassel, D.G.; DeWire, J.W.; Ehrlich, R.; Ferguson, T.; Gilchriese, M.G.D.; Gittelman, B.; Hartill, D.L.; Herrup, D.; Herzlinger, M.; Holzner, S.; Kandaswamy, J.; Kreinick, D.L.; Mistry, N.B.; Morrow, F.; Nordberg, E.; Perchonok, R.; Plunkett, R.; Silverman, A.; Stein, P.C.; Stone, S.; Weber, D.; Wilcke, R.; Sadoff, A.J.; Bebek, C.; Haggerty, J.; Hempstead, M.; Izen, J.M.; Loomis, W.A.; MacKay, W.W.; Pipkin, F.M.; Rohlf, J.; Tanenbaum, W.; Wilson, R.; Chadwick, K.; Chauveau, J.; Ganci, P.; Gentile, T.; Kagan, H.; Kass, R.; Melissinos, A.C.; Olsen, S.L.; Poling, R.; Rosenfeld, C.; Rucinski, G.; Thorndike, E.H.; Green, J.; Sannes, F.; Skubic, P.; Snyder, A.; Stone, R.; Brody, A.; Chen, A.; Goldberg, M.; Horwitz, N.; Lipari, P.; Kooy, H.; Moneti, G.C.; Pistilli, P.

    1982-01-01

    The charged multiplicity has been measured at the UPSILON(4S) and a value of 5.75 +- 0.1 +- 0.2 has been obtained for the mean charged multiplicity in B-meson decay. Combining this result with the measurement of prompt letpons from B decay, the values 4.1 +- 0.35 +- 0.2 and 6.3 +- 0.2 +- 0.2 are found for the semileptonic and nonleptonic charged multiplicities, respectively. If b→c dominance is assumed for the weak decay of the B meson, then the semileptonic multiplicity is consistent with the recoil mass determined from the lepton momentum spectrum

  8. Decay of homogeneous two-dimensional quantum turbulence

    Science.gov (United States)

    Baggaley, Andrew W.; Barenghi, Carlo F.

    2018-03-01

    We numerically simulate the free decay of two-dimensional quantum turbulence in a large, homogeneous Bose-Einstein condensate. The large number of vortices, the uniformity of the density profile, and the absence of boundaries (where vortices can drift out of the condensate) isolate the annihilation of vortex-antivortex pairs as the only mechanism which reduces the number of vortices, Nv, during the turbulence decay. The results clearly reveal that vortex annihilation is a four-vortex process, confirming the decay law Nv˜t-1 /3 where t is time, which was inferred from experiments with relatively few vortices in small harmonically trapped condensates.

  9. The decay of wood in landfills in contrasting climates in Australia

    Energy Technology Data Exchange (ETDEWEB)

    Ximenes, Fabiano, E-mail: fabiano.ximenes@dpi.nsw.gov.au [Forest Science, Agriculture NSW, New South Wales Department of Primary Industries, Level 12, 10 Valentine Ave, Parramatta, NSW 2150 (Australia); Björdal, Charlotte [Department of Conservation, Gothenburg University, Guldhedsgatan 5A, Box 130, SE-405 30 Göteborg (Sweden); Cowie, Annette [NSW Department of Primary Industries, Beef Industry Centre, Trevenna Rd., University of New England, Armidale, NSW 2351 (Australia); Barlaz, Morton [Dept. of Civil, Construction, & Environmental Eng., North Carolina State University, Box 7908, Raleigh, NC 27695-7908 (United States)

    2015-07-15

    Highlights: • We examine decay in wood from landfills in contrasting environments in Australia. • Analysis is based on changes in chemical composition and microscopy. • Climate did not influence levels of decay observed. • Microscopy of retrieved samples revealed most of the decay was aerobic in nature. • Current default factors for wood decay in landfills overestimate methane emissions. - Abstract: Wood products in landfill are commonly assumed to decay within several decades, returning the carbon contained therein to the atmosphere, with about half the carbon released as methane. However, the rate and extent of decay is not well known, as very few studies have examined the decay of wood products in landfills. This study reports on the findings from landfill excavations conducted in the Australian cities of Sydney and Cairns located in temperate and tropical environments, respectively. The objective of this study was to determine whether burial of the wood in warmer, more tropical conditions in Cairns would result in greater levels of decay than occurs in the temperate environment of Sydney. Wood samples recovered after 16–44 years in landfill were examined through physical, chemical and microscopic analyses, and compared with control samples to determine the carbon loss. There was typically little or no decay in the wood samples analysed from the landfill in Sydney. Although there was significant decay in rainforest wood species excavated from Cairns, decay levels for wood types that were common to both Cairns and Sydney landfills were similar. The current Intergovernmental Panel on Climate Change (IPCC, 2006) default decay factor for organic materials in landfills is 50%. In contrast, the carbon loss determined for Pinus radiata recovered from Sydney and Cairns landfills was 7.9% and 4.4%, respectively, and 0% for Agathis sp. This suggests that climate did not influence decay, and that the more extensive levels of decay observed for some wood samples

  10. The decay of wood in landfills in contrasting climates in Australia

    International Nuclear Information System (INIS)

    Ximenes, Fabiano; Björdal, Charlotte; Cowie, Annette; Barlaz, Morton

    2015-01-01

    Highlights: • We examine decay in wood from landfills in contrasting environments in Australia. • Analysis is based on changes in chemical composition and microscopy. • Climate did not influence levels of decay observed. • Microscopy of retrieved samples revealed most of the decay was aerobic in nature. • Current default factors for wood decay in landfills overestimate methane emissions. - Abstract: Wood products in landfill are commonly assumed to decay within several decades, returning the carbon contained therein to the atmosphere, with about half the carbon released as methane. However, the rate and extent of decay is not well known, as very few studies have examined the decay of wood products in landfills. This study reports on the findings from landfill excavations conducted in the Australian cities of Sydney and Cairns located in temperate and tropical environments, respectively. The objective of this study was to determine whether burial of the wood in warmer, more tropical conditions in Cairns would result in greater levels of decay than occurs in the temperate environment of Sydney. Wood samples recovered after 16–44 years in landfill were examined through physical, chemical and microscopic analyses, and compared with control samples to determine the carbon loss. There was typically little or no decay in the wood samples analysed from the landfill in Sydney. Although there was significant decay in rainforest wood species excavated from Cairns, decay levels for wood types that were common to both Cairns and Sydney landfills were similar. The current Intergovernmental Panel on Climate Change (IPCC, 2006) default decay factor for organic materials in landfills is 50%. In contrast, the carbon loss determined for Pinus radiata recovered from Sydney and Cairns landfills was 7.9% and 4.4%, respectively, and 0% for Agathis sp. This suggests that climate did not influence decay, and that the more extensive levels of decay observed for some wood samples

  11. Extracting and Using Photon Polarization Information in Radiative B Decays

    Energy Technology Data Exchange (ETDEWEB)

    Grossman, Yuval

    2000-05-09

    The authors discuss the uses of conversion electron pairs for extracting photon polarization information in weak radiative B decays. Both cases of leptons produced through a virtual and real photon are considered. Measurements of the angular correlation between the (K-pi) and (e{sup +}e{sup {minus}}) decay planes in B --> K*(--> K-pi)gamma (*)(--> e{sup +}e{sup {minus}}) decays can be used to determine the helicity amplitudes in the radiative B --> K*gamma decays. A large right-handed helicity amplitude in B-bar decays is a signal of new physics. The time-dependent CP asymmetry in the B{sup 0} decay angular correlation is shown to measure sin 2-beta and cos 2-beta with little hadronic uncertainty.

  12. Status of the Japanese decay heat standard

    International Nuclear Information System (INIS)

    Katakura, Jun-ichi

    1992-01-01

    Fission product decay heat power plays an important role in the safety evaluation of nuclear power plants, especially for the analysis of hypothetical reactor accident scenarios. The ANS-5.1 decay heat standard for safety evaluation issued in 1979 has been used widely, even in Japan. Since the issuance of the standard, several improvements have been made to measurements and summation calculations. Summation calculations, in particular, have improved because of the adoption of theoretically calculated decay energies for nuclides with incomplete decay data. Taking into consideration those improvements, the Atomic Energy Society of Japan (AESJ) organized a research committee on a standard for decay heat power in nuclear reactors in 1987. The committee issued its recommendation after more than 2 yr discussion. After the AESJ recommendation, the Nuclear Safety Commission of Japan also began to discuss whether the recommendation should be included in its regulatory guide. The commission concluded in 1992 that the recommendation should be approved for licensing analysis of reactors if three times the uncertainties attached to the recommendation are included in the analysis. The AESJ recommendation may now be used for the safety evaluation of reactors in Japan in addition to the standards already used, which include ANS-5.1 (1973), General Electric Corporation (GE) curve, and ANS-5.1 (1979)

  13. Rare B-meson decays at the crossroads

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Ahmed

    2016-07-15

    Experimental era of rare B-decays started with the measurement of B→K{sup *}γ by CLEO in 1993, followed two years later by the measurement of the inclusive decay B→X{sub s}γ, which serves as the standard candle in this field. The frontier has moved in the meanwhile to the experiments at the LHC, in particular, LHCb, with the decay B{sup 0}→μ{sup +}μ{sup -} at about 1 part in 10{sup 10} being the smallest branching fraction measured so far. Experimental precision achieved in this area has put the standard model to unprecedented stringent tests and more are in the offing in the near future. I review some key measurements in radiative, semileptonic and leptonic rare B-decays, contrast them with their estimates in the SM, and focus on several mismatches reported recently. They are too numerous to be ignored, yet, standing alone, none of them is significant enough to warrant the breakdown of the SM. Rare B-decays find themselves at the crossroads, possibly pointing to new horizons, but quite likely requiring an improved theoretical description in the context of the SM. An independent precision experiment such as Belle II may help greatly in clearing some of the current experimental issues.

  14. Rare B-meson decays at the crossroads

    International Nuclear Information System (INIS)

    Ali, Ahmed

    2016-07-01

    Experimental era of rare B-decays started with the measurement of B→K * γ by CLEO in 1993, followed two years later by the measurement of the inclusive decay B→X s γ, which serves as the standard candle in this field. The frontier has moved in the meanwhile to the experiments at the LHC, in particular, LHCb, with the decay B 0 →μ + μ - at about 1 part in 10 10 being the smallest branching fraction measured so far. Experimental precision achieved in this area has put the standard model to unprecedented stringent tests and more are in the offing in the near future. I review some key measurements in radiative, semileptonic and leptonic rare B-decays, contrast them with their estimates in the SM, and focus on several mismatches reported recently. They are too numerous to be ignored, yet, standing alone, none of them is significant enough to warrant the breakdown of the SM. Rare B-decays find themselves at the crossroads, possibly pointing to new horizons, but quite likely requiring an improved theoretical description in the context of the SM. An independent precision experiment such as Belle II may help greatly in clearing some of the current experimental issues.

  15. Single particle level scheme for alpha decay

    International Nuclear Information System (INIS)

    Mirea, M.

    1998-01-01

    The fine structure phenomenon in alpha decay was evidenced by Rosenblum. In this process the kinetic energy of the emitted particle has several determined values related to the structure of the parent and the daughter nucleus. The probability to find the daughter in a low lying state was considered strongly dependent on the spectroscopic factor defined as the square of overlap between the wave function of the parent in the ground state and the wave functions of the specific excited states of the daughter. This treatment provides a qualitative agreement with the experimental results if the variations of the penetrability between different excited states are neglected. Based on single particle structure during fission, a new formalism explained quantitatively the fine structure of the cluster decay. It was suggested that this formalism can be applied also to alpha decay. For this purpose, the first step is to construct the level scheme of this type of decay. Such a scheme, obtained with the super-asymmetric two-center potential, is plotted for the alpha decay of 223 Ra. It is interesting to note that, diabatically, the level with spin 3/2 emerging from 1i 11/2 (ground state of the parent) reaches an excited state of the daughter in agreement with the experiment. (author)

  16. The Decay of Motor Memories Is Independent of Context Change Detection.

    Directory of Open Access Journals (Sweden)

    Andrew E Brennan

    2015-06-01

    Full Text Available When the error signals that guide human motor learning are withheld following training, recently-learned motor memories systematically regress toward untrained performance. It has previously been hypothesized that this regression results from an intrinsic volatility in these memories, resulting in an inevitable decay in the absence of ongoing error signals. However, a recently-proposed alternative posits that even recently-acquired motor memories are intrinsically stable, decaying only if a change in context is detected. This new theory, the context-dependent decay hypothesis, makes two key predictions: (1 after error signals are withheld, decay onset should be systematically delayed until the context change is detected; and (2 manipulations that impair detection by masking context changes should result in prolonged delays in decay onset and reduced decay amplitude at any given time. Here we examine the decay of motor adaptation following the learning of novel environmental dynamics in order to carefully evaluate this hypothesis. To account for potential issues in previous work that supported the context-dependent decay hypothesis, we measured decay using a balanced and baseline-referenced experimental design that allowed for direct comparisons between analogous masked and unmasked context changes. Using both an unbiased variant of the previous decay onset analysis and a novel highly-powered group-level version of this analysis, we found no evidence for systematically delayed decay onset nor for the masked context change affecting decay amplitude or its onset time. We further show how previous estimates of decay onset latency can be substantially biased in the presence of noise, and even more so with correlated noise, explaining the discrepancy between the previous results and our findings. Our results suggest that the decay of motor memories is an intrinsic feature of error-based learning that does not depend on context change detection.

  17. The Decay of Motor Memories Is Independent of Context Change Detection

    Science.gov (United States)

    Brennan, Andrew E.; Smith, Maurice A.

    2015-01-01

    When the error signals that guide human motor learning are withheld following training, recently-learned motor memories systematically regress toward untrained performance. It has previously been hypothesized that this regression results from an intrinsic volatility in these memories, resulting in an inevitable decay in the absence of ongoing error signals. However, a recently-proposed alternative posits that even recently-acquired motor memories are intrinsically stable, decaying only if a change in context is detected. This new theory, the context-dependent decay hypothesis, makes two key predictions: (1) after error signals are withheld, decay onset should be systematically delayed until the context change is detected; and (2) manipulations that impair detection by masking context changes should result in prolonged delays in decay onset and reduced decay amplitude at any given time. Here we examine the decay of motor adaptation following the learning of novel environmental dynamics in order to carefully evaluate this hypothesis. To account for potential issues in previous work that supported the context-dependent decay hypothesis, we measured decay using a balanced and baseline-referenced experimental design that allowed for direct comparisons between analogous masked and unmasked context changes. Using both an unbiased variant of the previous decay onset analysis and a novel highly-powered group-level version of this analysis, we found no evidence for systematically delayed decay onset nor for the masked context change affecting decay amplitude or its onset time. We further show how previous estimates of decay onset latency can be substantially biased in the presence of noise, and even more so with correlated noise, explaining the discrepancy between the previous results and our findings. Our results suggest that the decay of motor memories is an intrinsic feature of error-based learning that does not depend on context change detection. PMID:26111244

  18. Decay rates of various bottomonium systems

    International Nuclear Information System (INIS)

    Kim, S.

    1995-01-01

    Using the Bodwin-Braaten-Lepage factorization theorem in heavy quarkonium decay and production processes, the authors calculated matrix elements associated with S- and P-wave bottomonium decays via lattice QCD simulation methods. In this work, they report preliminary results on the operator matching between the lattice expression and the continuum expression at one loop level. Phenomenological implications are discussed using these preliminary MS matrix elements

  19. Exotic muon decays and searches for neutrino oscillations

    International Nuclear Information System (INIS)

    Herczeg, P.

    1997-06-01

    Experiments that search for anti ν e 's from μ + -decay are sensitive not only to oscillations of neutrinos into anti ν e , but also to μ + → e + anti ν e n x decays, where n x is a neutrino or an antineutrino. The author considers such muon decays and the possible size of their branching ratios in left-right symmetric models and in the minimal supersymmetric standard model with R-parity violation

  20. Explicit solutions for exit-only radioactive decay chains

    International Nuclear Information System (INIS)

    Yuan, Ding; Kernan, Warnick

    2007-01-01

    In this study, we extended Bateman's [Proc. Cambridge Philos. Soc. 15, 423 (1910)] original work for solving radioactive decay chains and explicitly derived analytic solutions for generic exit-only radioactive decay problems under given initial conditions. Instead of using the conventional Laplace transform for solving Bateman's equations, we used a much simpler algebraic approach. Finally, we discuss methods of breaking down certain classes of large decay chains into collections of simpler chains for easy handling

Some links on this page may take you to non-federal websites. Their policies may differ from this site.