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P. Kienle

Publications and source records attributed to P. Kienle.

At least 55 records · Page 3Linked to original sources
arXiv2009

Measurement of the in-medium K0 inclusive cross section in pi- -induced reactions at 1.15 GeV/c

The K0 meson production by pi- mesons of 1.15 GeV/c momentum on C, Al, Cu, Sn and Pb nuclear targets was measured with the FOPI spectrometer at the SIS accelerator of GSI. Inclusive production cross-sections and the momentum distributions of K0 mesons are compared to scaled elementary production cross-sections and to predictions of theoretical models describing the in-medium production of kaons. The data represent a new reference for those models, which are widely used for interpretation of the strangeness-production in heavy-ion collisions. The presented results demonstrate the sensitivity of the kaon production to the reaction amplitudes inside nuclei and point to the existence of a repulsive KN-potential of 20+-5 MeV at normal nuclear matter density.

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arXiv2008

On the time-modulation of the K-shell electron capture decay of H-like 140Pr58+ ions produced by neutrino-flavour mixing

According to recent experimental data at GSI, the rate of the number of daughter ions 140Ce58+, produced by the nuclear K-shell electron capture (EC) decay of the H-like ion 140Pr58+, is modulated in time with a period T_d = 7.06(8) sec and an amplitude a_(EC) = 0.20(2). We show that this phenomenon can be explained by neutrino-flavour mixing and derive a value for the difference of squared masses Delta m^2_(21) = m^2_2 - m^2_1 = 2.22(3)x10^(-4) eV^2.

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arXiv2008

Can the "Darmstadt oscillations" be treated as two closely spaced mass-eigenstates of the H-like mother ions ?

We discuss the proposal that the "Darmstadt oscillations" of the orbital K-shell electron capture decay (EC) rate of the H-like heavy ions are caused by quantum beats of two coherently excited, closely spaced mass-eigenstates of decaying H-like heavy ions. We show that such a mechanism to explain the time modulation of the EC-decay rates of the H-like heavy ions leads to the time modulation of the beta^+ decay rate of these ions with the same period. Such a time-dependence of the beta^+ decay rate of the H-like heavy ions contradicts the experimental data of GSI.

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arXiv2008

First-Forbidden Continuum- and Bound-State beta^- -Decay Rates of Bare 205Hg80+ and 207Tl81+ Ions

We calculate the decay rates lambda_(beta^-_c) and lambda_(beta^-_b) of the continuum- and bound-state beta^- decays for bare 205Hg80+ and 207Tl81+ ions. For the ratio of the decay rates R_(b/c) = lambda_(beta^-_b)/lambda_(beta^-_c) we obtain the values R_(b/c) = 0.161 and R_(b/c) = 0.190 for bare 205Hg80+ and 207Tl81+ ions, respectively. The theoretical value of the ratio R_(b/c) = 0.190 for the decays of 207Tl81+ agrees within 1% of accuracy with the experimental data R^exp_(b/c) = 0.188(18), obtained at GSI. The theoretical ratio R_(b/c) = 0.161 for 205Hg80+ is about 20% smaller than the experimental value R^exp_(b/c) = 0.20(2), measured recently at GSI.

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arXiv2008

Comments on "Rates of processes with coherent production of different particles and the GSI time anomaly"by C. Giunti, Phys. Lett. B 665, 92 (2008), 0805.0431

We give comments on the recent paper by Giunti (Phys. Lett. B 665, 92 (2008), arXiv: 0805.0431 [hep-ph]) with a critique of our explanation of the experimentally observed periodic time-dependence of the interference term in the rate of the K-shell electron capture decay of the H-like ions 140Pr58+ and 142Pm60+ as a two-neutrino-flavour mixing. We show also that this phenomenon cannot be explained by a coherent mixing of two states of a mother ion as proposed by Giunti.

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arXiv2008

Comment on the paper "Search for oscillation of the electron-capture decay probability of $^{142}$Pm" at arXiv:0807.0649v1

It is argued that orbital electron-capture decays of neutral $^{142}$Pm atoms implanted into the lattice of a solid (LBNL experiment) do not fulfil the constraints of true two-body beta decays, since momentum as well as energy of the final state are distributed among three objects, namely the electron neutrino, the recoiling daughter atom and the lattice phonons. To our understanding, this could be a reason for the non-observation of a periodic time modulation in the number of electron-capture decays of implanted neutral $^{142}$Pm atoms.

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arXiv2008

On the Time-Modulation of the beta^+$-Decay Rate of H-like 140Pr58+ Ion

According to recent experimental data at GSI, the rates of the number of daughter ions, produced by the nuclear K-shell electron capture (EC) decays of the H-like ions 140Pr58+ and 142Pm60+, are modulated in time with periods T_(EC) simeq 7 s and amplitudes a_(EC) simeq 0.20. We study a possible time-dependence of the nuclear positron (beta^+) decay rate of the H-like 140Pr58+. We show that the time-dependence of the beta^+ decay rate of the H-like 140Pr58+ ion as well as any H-like heavy ions cannot be observed. This result can be used as a prediction for future analysis of the time-dependence of the beta^+ decay rates of the H-like heavy ions 140Pr58+ and 142Pm60+ at GSI for the test of the measuring method.

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arXiv2008

Weak decays of H-like 140Pr58+ and He-like 140Pr57+ ions

The nuclear K-shell electron-capture (EC)and positron (beta+) decay constants, lambda_(EC) and lambda_(beta^+) of H-like 140Pr58+ and He-like 140Pr57+ ions, measured recently in the ESR ion storage ring at GSI, were calculated using standard weak interaction theory. The calculated ratios R = lambda_(EC)/lambda_(beta^+) of the decay constants agree with the experimental values within an accuracy better than 3 %.

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arXiv2008

Observation of Non-Exponential Orbital Electron Capture Decays of Hydrogen-Like $^{140}$Pr and $^{142}$Pm Ions

We report on time-modulated two-body weak decays observed in the orbital electron capture of hydrogen-like $^{140}$Pr$^{59+}$ and $^{142}$Pm$^{60+}$ ions coasting in an ion storage ring. Using non-destructive single ion, time-resolved Schottky mass spectrometry we found that the expected exponential decay is modulated in time with a modulation period of about 7 seconds for both systems. Tentatively this observation is attributed to the coherent superposition of finite mass eigenstates of the electron neutrinos from the weak decay into a two-body final state.

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arXiv2007

$Λd$ correlations from the $^4$He(stopped-$K^-$,$d$) reaction

We have observed an intense high-energy component in an inclusive $^4$He(stopped $K^-$, $d$) spectrum. For back-to-back $Λd$ pairs a prominent event cluster has been found just below the $m_{^4\textrm{He}}+m_{K^-}-m_{n}$ mass threshold in the $Λd$ invariant mass spectrum of $Λdn$ events, which is evidence for a three-nucleon absorption process of $K^-$ in $^4$He. In addition, an appreciable strength is revealed below $\sim$3220 MeV/$c^2$. Well separated $Σ^0 dn$ events show a peak similar to the case of $Λdn$.

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arXiv2007

$ΛN$ correlations from the stopped $K^-$ reaction on ${}^4$He

We have investigated correlations of coincident $ΛN$ pairs from the stopped $K^-$ reaction on ${}^4$He, and clearly observed $Λp$ and $Λn$ branches of the two-nucleon absorption process in the $ΛN$ invariant mass spectra. In addition, non-mesonic reaction channels, which indicate possible exotic signals for the formation of strange multibaryon states, have been identified.

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arXiv2007

Measurement of the $β^+$ and orbital electron-capture decay rates in fully-ionized, hydrogen-like, and helium-like $^{140}$Pr ions

We report on the first measurement of the $β^+$- and orbital electron capture decay rates of $^{140}$Pr nuclei with the most simple electron configurations: bare nuclei, hydrogen-like and helium-like ions. The measured electron capture decay constant of hydrogen-like $^{140}$Pr$^{58+}$ ions is about 50% larger than that of helium-like $^{140}$Pr$^{57+}$ ions. Moreover, $^{140}$Pr ions with one bound electron decay faster than neutral $^{140}$Pr$^{0+}$ atoms with 59 electrons. To explain this peculiar observation one has to take into account the conservation of the total angular momentum, since only particular spin orientations of the nucleus and of the captured electron can contribute to the allowed decay.

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arXiv2007

Search for strange tribaryon states in the inclusive ^4He(K^{-}_{stopped}, p) reaction

A search for tribaryon states was performed at KEK-PS. We adopted the $^4$He($K^-_{stopped}, p)$ reaction to populate the states with strangeness -1, charge 0 and isospin 1. No significant narrow structure was observed in the mass region from 3000 to 3200 MeV/c^2 in an inclusive missing mass spectrum. The upper limit of the formation branching ratio was determined to be ($1\sim3)\times 10^{-4}$, ($0.7\sim2)\times 10^{-3}$ and ($2\sim8) \times 10^{-3}$/($stopped K^{-}$) with 95 % confidence level for narrow states with an assumed width of 0, 20 and 40 MeV/c^2, respectively.

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arXiv2007

Precision measurement of the $3d \to 2p$ x-ray energy in kaonic $^4$He

We have measured the Balmer-series x-rays of kaonic $^4$He atoms using novel large-area silicon drift x-ray detectors in order to study the low-energy $\bar{K}$-nucleus strong interaction. The energy of the $3d \to 2p$ transition was determined to be 6467 $\pm$ 3 (stat) $\pm$ 2 (syst) eV. The resulting strong-interaction energy-level shift is in agreement with theoretical calculations, thus eliminating a long-standing discrepancy between theory and experiment.

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arXiv2007

Search for a kaonic nuclear state via $^4$He$(K^-, N)$

Very recently, we have performed a couple of experiments, {\it{KEK PS-E549/E570}}, for the detailed study of the strange tribaryon $S^0(3115)$ obtained in {\it{KEK PS-E471}}. These experiments were performed to accumulate much higher statistics with improved experimental apparatusespecially for the better proton spectroscopy of the $^4$He({\it{stopped K}}$^-$, {\it{N}}) reaction. In contrast to the previous proton spectrum, no narrow ($\sim$ 20 MeV) peak structure was found either in the inclusive $^4$He({\it{stopped K}}$^-$, {\it{p}}) or in the semi-inclusive $^4$He({\it{stopped K}}$^-$, {\it{p}}$X^\pm$) reaction channel, which is equivalent to the previous $E471$ event trigger condition. Detailed analysis of the present data and simulation shows that the peak, corresponding to $S^0(3115)$, has been an experimental artifact. Present analysis does not exclude the possible existence of a much wider structure. To be sensitive to such structure and for better understanding of the non-mesonic $K^-$ absorption reaction channel, detailed analysis of the data is in progress.

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arXiv2006

Phenomenological model of the Kaonic Nuclear Cluster K^-pnn in the ground state

A phenomenological model, proposed for the Kaonic Nuclear Cluster (KNC) K^-pp, is applied to the theoretical analysis of the KNC K^-pnn (or S^0). The theoretical values of the binding energy and the width are equal to epsilon_(S^0) = - 197 MeV and Gamma_(S^0) = 16 MeV. They agree well with the experimental data epsilon^(exp)_(S^0) = - 194.0(+ 1.5/- 4.4) MeV and Gamma^(exp)_(S^0) < 21 MeV} (PLB 597, 263 (2004)) and the theoretical values epsilon_(S^0) = - 191 MeV and Gamma_(S^0) = 13 MeV, obtained by Akaishi and Yamazaki within the potential model approach.

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arXiv2006

Phenomenological model of the Kaonic Nuclear Cluster K^-pp in the ground state

A phenomenological model is proposed for the analysis of the properties of the Kaonic Nuclear Cluster (KNC) Kpp in its ground state. Inside the KNC K^-pp we describe the relative motion of the protons in the pp pair and the motion of the K^- meson relative to the pp pair in terms of wave functions of 3-dimensional harmonic oscillators. The interaction strength is parameterised in our model by the frequency of the longitudinal oscillation of the K^- meson relative to the pp pair. This parameter was determined with the binding energy and width of the strange baryon Lambda(1405) by assuming that it is a bound state of the K^-p pair. In terms of this interaction strength we calculate the binding energy epsilon_(Kpp) = - 118 MeV, the partial widths of non-pionic decay channels and the total width, Gamma_(Kpp) = 58 MeV. This agrees well with the experimental data by the FINUDA Collaboration (PRL 94, 212303 (2005)): epsilon_exp = - 115(+6/-5) MeV and Gamma_exp = 67(+14/-11) MeV. The discrepancy with the results, obtained by Akaishi and Yamazaki within the potential model approach, is discussed.

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