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1.
We present numerical estimates for the various signatures of a neutral Higgs particle produced in the radiative decaysVH+γ, of a heavy vector onium stateV(≡J/ ψ ,Υ,Υ t ). We suggest to enhance the Higgs signal by requiring a correlation with weakly decaying states (τ, charm, bottom) or with strange particles from charm and bottom. Rates for the processes $$\begin{gathered} e^ + e^ - \to V \to H + \gamma \to \geqq 1lepton + \gamma + anything, \hfill \\ \geqq 2kaons + \gamma + anything \hfill \\ \end{gathered} $$ are presented, and the effects of the lepton energy cuts on the first of the two processes are evaluated.  相似文献   

2.
The static hyperfine field ofB hf 4.2k (ErHo) = 739(18)T of a ferromagnetic holmium single crystal polarized in an external magnetic field of ± 0.48T at ~4.2K was used for integral perturbed γ-γ angular correlation (IPAQ measurements of the g-factors of collective states of166Er. The 1,200y 166m Ho activity was used which populates the ground state band and the γ vibrational band up to high spins. The results: $$\begin{gathered} g(4_g^ + ) = + 0.315(16) \hfill \\ g(6_g^ + ) = + 0.258(11) \hfill \\ g(8_g^ + ) = + 0.262(47)and \hfill \\ g(6_\gamma ^ + ) = + 0.254(32) \hfill \\ \end{gathered}$$ exhibit a significant reduction of the g-factors with increasing rotational angular momentum. The followingE2/M1 mixing ratios of interband transitions were derived from the angular correlation coefficients: $$\begin{gathered} 5_\gamma ^ + \Rightarrow 4_g^ + :\delta (810keV) = - (36_{ - 7}^{ + 11} ) \hfill \\ 7_\gamma ^ + \Rightarrow 6_g^ + :\delta (831keV) = - (18_{ - 2}^{ + 3} )and \hfill \\ 7_\gamma ^ + \Rightarrow 8_g^ + :\delta (465keV) = - (63_{ - 12}^{ + 19} ). \hfill \\ \end{gathered}$$ The results are discussed and compared with theoretical predictions.  相似文献   

3.
Using the atomic beam magnetic resonance method, precision measurements of the hyperfine structure and Zeeman interactions have been performed in the ground state 4f 126s 2 3 H 6 of167Er. The experimental data were analyzed using an effective operator parametrized in the space of states of the ground state multiplet. It yielded eight effective hyperfine structure and Zeeman interaction constants which served to calculate the seven hyperfine separations of the ground state. The results are: $$\begin{gathered} 2F 2F' v_{FF'} (MHz) \hfill \\ 5 7 - 354.371 9409 (27) \hfill \\ 7 9 - 2{\text{78}}{\text{.231}} {\text{8263(14)}} \hfill \\ {\text{9}} 11 - 69.050 7785 (4) \hfill \\ 11 13 + 302.735 3731(12) \hfill \\ 13 15 + 866.691 3871(10) \hfill \\ 15 17 + 1,652.383 5154 (6) \hfill \\ 17 19 + 2,689.380 8050(10) \hfill \\ \end{gathered}$$ From the effective Zeeman interaction constants it was possible to determine an improvedg I -value, uncorrected for atomic diamagnetism: $$ g_I = + 0.086 775 (19) \cdot 10^{ - 3}$$ Furthermore a hexadecapole interaction corresponding to a diagonal hexadecapole interaction constant $$A_4 = - 16 (10) Hz$$ could be established which is of the order of magnitude expected from Coulomb excitation experiments as well as theoretical calculations.  相似文献   

4.
205,207Po have keen implanted with an isotope separator on-line into cold host matrices of Fe, Ni, Zn and Be. Nuclear magnetic resonance of oriented207Po has been observed in Fe and Ni, of205Po in Fe. The resonance frequencies for zero external field are $$\begin{gathered} v_L (^{207} Po\underline {Fe} ) = 575.08(20)MHz \hfill \\ v_L (^{207} Po\underline {Ni} ) = 160.1(8)MHz \hfill \\ v_L (^{205} Po\underline {Fe} ) = 551.7(8)MHz. \hfill \\ \end{gathered} $$ From the dependence of the resonance frequency on external magnetic field theg-factor of207Po was derived as $$g(^{207} Po) = + 0.31(22).$$ Using this value the magnetic hyperfine fields of Po in Fe and Ni were obtained as $$\begin{gathered} B_{hf} (Po\underline {Fe} ) = + 238(16)T \hfill \\ B_{hf} (Po\underline {Ni} ) = 66.3(4.6)T. \hfill \\ \end{gathered}$$ Theg-factor of205Po follows as $$g(^{205} Po) = + 0.304(22).$$ From the temperature dependence of the anisotropies ofγ-lines in the decay of205,207Po the multipole mixing of several transitions was derived. The electric interaction frequenciesv Q=eQVzz/h in the hosts Zn and Be were measured as $$\begin{gathered} v_Q (^{207} Po\underline {Zn} ) = + 42(3)MHz \hfill \\ v_Q (^{207} Po\underline {Be} ) = - 70(20)MHz \hfill \\ v_Q (^{205} Po\underline {Be} ) = - 42(17)MHz. \hfill \\ \end{gathered}$$   相似文献   

5.
Let $$\begin{gathered} u^* = u + \in \eta (x,{\text{ }}t,{\text{ }}u), \hfill \\ \hfill \\ \hfill \\ x^* = x + \in \xi (x, t, u{\text{),}} \hfill \\ \hfill \\ \hfill \\ {\text{t}}^{\text{*}} = {\text{ }}t + \in \tau {\text{(}}x,{\text{ }}t,{\text{ }}u), \hfill \\ \end{gathered}$$ be an infinitesimal invariant transformation of the evolution equation u t =H(x,t,u,?u/?x,...,? n :u/?x n . In this paper we give an explicit expression for \(\eta ^{X^i }\) in the ‘determining equation’ $$\eta ^T = \sum\limits_{i = 1}^n {{\text{ }}\eta ^{X^i } {\text{ }}\frac{{\partial H}}{{\partial u_i }} + \eta \frac{{\partial H}}{{\partial u_{} }} + \xi \frac{{\partial H}}{{\partial x}} + \tau } \frac{{\partial H}}{{\partial t}},$$ where u i =? i u/?x i . By using this expression we derive a set of equations with η, ξ, τ as unknown functions and discuss in detail the cases of heat and KdV equations.  相似文献   

6.
In this paper we will study the nonlinear Schrödinger equations: $$\begin{gathered} i\partial _t u + \tfrac{1}{2}\Delta u = \left| u \right|^2 u, (t,x) \in \mathbb{R} \times \mathbb{R}_x^n , \hfill \\ u(0,x) = \phi (x), x \in \mathbb{R}_x^n \hfill \\ \end{gathered} $$ . It is shown that the solutions of (*) exist and are analytic in space variables fort∈??{0} if φ(x) (∈H 2n+1,2(? x n )) decay exponentially as |x|→∞ andn≧2.  相似文献   

7.
Using the atomic beam magnetic resonance method the experimental hyperfine structure data of the 5d 26s 2 3 F 2 ground state of177Hf and179Hf described in a previous paper [1] have been completed. After applying corrections due to perturbations by other fine structure levels of the configuration 5d 26s 2 we got the following multipole interaction constants: $$\begin{gathered} ^{177} Hf:A = 113.43314 (7) MHz B = 624.3293 (13) MHz \hfill \\ C = 0.27 (18) KHz D = 0.045 (40) KHz \hfill \\ ^{179} Hf: A = - 71.42891 (9) MHz B = 705.5181 (24) MHz \hfill \\ C = - 0.43 (20) MHz D = 0.07 (6) KHz. \hfill \\ \end{gathered} $$ By measuring rf transitions at magnetic fields between 1100 and 1550 Gauss the nuclear ground state magnetic dipole moments were determined. The results are: $$\mu _I (^{177} Hf) = 0.7836 (6) \mu _N , \mu _I (^{179} Hf) = - 0.6329 (13) \mu _N $$ (uncorrected for diamagnetic shielding).  相似文献   

8.
By applying the Feynman-Hellmann theorem to \(q\bar q\) systems we find the following bounds on quark mass differences from the spectrum ofall quarkonium states $$\begin{gathered} 0.27 \leqq m_s - m_u \leqq 0.45GeV \hfill \\ 1.23 \leqq m_c - m_s \leqq 1.46GeV \hfill \\ 3.30 \leqq m_b - m_c \leqq 3.55GeV. \hfill \\ \end{gathered}$$ As best values we derive $$\begin{gathered} m_u = m_d = 0.31GeV,m_s = 0.62GeV, \hfill \\ m_c = 1.91GeV,m_b = 5.27GeV. \hfill \\ \end{gathered}$$   相似文献   

9.
The hyperfine structure and the Stark effect shift of the 4d5s5p z 2 F 5/2 states in the Y I spectrum were investigated by level-crossing technique. Between the Zeeman effect region and the Paschen-Back region of hyperfine structure states some of the levels cross. The resonance radiation of these coherently excited levels show an interference effect of the scattering amplitudes in the crossing region. The level-crossing signals give information about hfs splitting and lifetime of the excited states under investigation. The magnetic hfs splitting factorsA of the 4d5s5p z 2 F 5/2, 7/2 states and their lifetimes were deduced. $$\begin{gathered} |A (z^2 F_{5/2} )| = (23.8 \pm 0.04) MHz \frac{{g_J }}{{0.854}} \hfill \\ |A (z^2 F_{7/2} )| = (84.08 \pm 0.01) MHz \frac{{g_J }}{{1.148}} \hfill \\ \tau (z^2 F_{5/2} ) = (46 \pm 3) 10^{ - 9} s \frac{{0.854}}{{g_J }} \hfill \\ \tau (z^2 F_{7/2} ) = (44 \pm 4) 10^{ - 9} s \frac{{1.148}}{{g_J }}. \hfill \\ \end{gathered} $$ With an electric field parallel to the magnetic field a shift of the level-crossing signals of the 4d5s5p z 2 F 5/2, 7/2 states was observed, and the Stark constants β were deduced. $$\begin{gathered} |\beta (z^2 F_{5/2} )| = (0.0020 \pm 0.0002) MHz/(kV/cm)^2 \hfill \\ |\beta (z^2 F_{7/2} )| = (0.0025 \pm 0.0015) MHz/(kV/cm)^2 . \hfill \\ \end{gathered} $$   相似文献   

10.
11.
Results of the search for rare radiative decay modes of the ?-meson performed with the Neutral Detector at the VEPP-2M collider are presented. For the first time upper limits for the branching ratios of the following decay modes have been placed at 90% confidence level: $$\begin{gathered} B(\phi \to \eta '\gamma )< 4 \cdot 10^{ - 4} , \hfill \\ B(\phi \to \pi ^0 \pi ^0 \gamma )< 10^{ - 3} , \hfill \\ B(\phi \to f_0 (975)\gamma )< 2 \cdot 10^{ - 3} , \hfill \\ B(\phi \to H\gamma )< 3 \cdot 10^{ - 4} , \hfill \\ \end{gathered} $$ whereH is a scalar (Higgs) boson with a mass 600 MeV<m H <1000 MeV, the real measurement isB(φH γB(H→2π0)<0.8·10-4, the quoted result is model dependent, as explained in the text, $$\begin{gathered} B(\phi \to a\gamma ) \cdot B(a \to e^ + e^ - )< 5 \cdot 10^{ - 5} , \hfill \\ B(\phi \to a\gamma ) \cdot B(a \to \gamma \gamma )< 2 \cdot 10^{ - 3} , \hfill \\ \end{gathered} $$ wherea is a particle with a low mass and a short lifetime, $$B(\phi \to a\gamma )< 0.7 \cdot 10^{ - 5} ,$$ wherea is a particle with a low mass not observed in the detector.  相似文献   

12.
Radio frequency spectra of CsF in the rotational stateJ=1 have been measured for the vibrational statesv=0, 1,..., 8 using the molecular beam electric resonance method. The analysis of the spectra yields the electric dipole moment μv and the quadrupole coupling constanteq v Q connected with the quadrupole moment of the Cs nucleus. The results are: $$\begin{gathered} \mu _\upsilon = 7.8478 + 0.07026(\upsilon + 1/2) + 0.000195(\upsilon + 1/2)^2 debye \hfill \\ eq_\upsilon Q/h = 1245.2 - 16.2(\upsilon + 1/2) + 0.31(\upsilon + 1/2)^2 kHz. \hfill \\ \end{gathered} $$   相似文献   

13.
Theg-factor of the 181 keV-level of99Tc has been redetermined by the spin rotation method. Measurements with polycrystalline sources of Tc in Fe, Co, and Ni yielded values of the hyperfine fields at the Tc nucleus. $$\begin{gathered} g = + 1.310(25) \hfill \\ H_{hf} (Tc{\mathbf{ }}in{\mathbf{ }}Fe) = ( - )290(15)kOe \hfill \\ H_{hf} (Tc{\mathbf{ }}in{\mathbf{ }}Co) = ( - )170(5)kOe \hfill \\ H_{hf} (Tc{\mathbf{ }}in{\mathbf{ }}Ni) = - 47.8(1.5)kOe. \hfill \\ \end{gathered} $$   相似文献   

14.
Applying a recently developed evaporation technique for refractory elements the following results have been obtained for Ta181 in an atomic beam magnetic resonance experiment studying the hyperfine structure of 3 levels of the ground state multiplet4 F: $$\begin{gathered} g_J (^4 F_{3/2} ) = 0.45024 (4) \hfill \\ \Delta v (^4 F_{3/2} ;F = 5 \leftrightarrow F = 4) = 1822.389 (6) MHz \hfill \\ \Delta v (^4 F_{3/2} ;F = 4 \leftrightarrow F = 3) = 2325.537 (2) MHz \hfill \\ \Delta v (^4 F_{5/2} ;F = 6 \leftrightarrow F = 5) = 1451.476 (7) MHz \hfill \\ \Delta v (^4 F_{5/2} ;F = 5 \leftrightarrow F = 4) = 1537.530 (8) MHz \hfill \\ \Delta v (^4 F_{5/2} ;F = 4 \leftrightarrow F = 3) = 1444.685 (2) MHz \hfill \\ \Delta v (^4 F_{7/2} ;F = 4 \leftrightarrow F = 3) = 1218.372 (2) MHz. \hfill \\ \end{gathered}$$ From these measurements the following constants of the magnetic dipole interaction (A) and the electric quadrupole interaction (B) have been derived: $$\begin{gathered} A (^4 F_{3/2} ) = 509.0801 (8) MHz \hfill \\ B (^4 F_{3/2} ) = - 1012.251 (8) MHz \hfill \\ A (^4 F_{5/2} ) = 313.4681 (8) MHz \hfill \\ B (^4 F_{5/2} ) = - 834.820 (12) MHz. \hfill \\ \end{gathered}$$   相似文献   

15.
Thed-dimensional, nearest-neighbor disordered Ising ferromagnet: $$H = - \sum {J_{ij} \sigma _i \sigma _j }$$ is studied as a function of both temperature,T, and a disorder parameter,λ, which measures the size of fluctuations of couplingsJ ij ≧0. A finite-size scaling correlation length,ζ f (T, λ), is defined in terms of the magnetic response of finite samples. This correlation length is shown to be equivalent, in the scaling sense, to the quenched average correlation lengthζ(T, λ), defined as the asymptotic decay rate of the quenched average two-point function. Furthermore, the magnetic response criterion which definesζ f is shown to have a scale-invariant property at the critical point. The above results enable us to prove that the quenched correlation length satisfies: $$C\left| {\log \xi (T)} \right|\xi (T) \geqq \left| {T - T_c } \right|^{ - {2 \mathord{\left/ {\vphantom {2 d}} \right. \kern-\nulldelimiterspace} d}}$$ which implies the boundv≧2/d for the quenched correlation length exponent.  相似文献   

16.
Using algebraic methods, we find the three-loop relation between the bare and physical couplings of one-flavourD-dimensional QED, in terms of Γ functions and a singleF 32 series, whose expansion nearD=4 is obtained, by wreath-product transformations, to the order required for five-loop calculations. Taking the limitD→4, we find that the \(\overline {MS} \) coupling \(\bar \alpha (\mu )\) satisfies the boundary condition $$\begin{gathered} \frac{{\bar \alpha (m)}}{\pi } = \frac{\alpha }{\pi } + \frac{{15}}{{16}}\frac{{\alpha ^3 }}{{\pi ^3 }} + \left\{ {\frac{{11}}{{96}}\zeta (3) - \frac{1}{3}\pi ^2 \log 2} \right. \hfill \\ \left. { + \frac{{23}}{{72}}\pi ^2 - \frac{{4867}}{{5184}}} \right\}\frac{{\alpha ^4 }}{{\pi ^4 }} + \mathcal{O}(\alpha ^5 ), \hfill \\ \end{gathered} $$ wherem is the physical lepton mass and α is the physical fine structure constant. Combining this new result for the finite part of three-loop on-shell charge renormalization with the recently revised four-loop term in the \(\overline {MS} \) β-function, we obtain $$\begin{gathered} \Lambda _{QED}^{\overline {MS} } \approx \frac{{me^{3\pi /2\alpha } }}{{(3\pi /\alpha )^{9/8} }}\left( {1 - \frac{{175}}{{64}}\frac{\alpha }{\pi } + \left\{ { - \frac{{63}}{{64}}\zeta (3)} \right.} \right. \hfill \\ \left. { + \frac{1}{2}\pi ^2 \log 2 - \frac{{23}}{{48}}\pi ^2 + \frac{{492473}}{{73728}}} \right\}\left. {\frac{{\alpha ^2 }}{{\pi ^2 }}} \right), \hfill \\ \end{gathered} $$ at the four-loop level of one-flavour QED.  相似文献   

17.
18.
Excited atomic2 P 3/2-states of radioactive Rb isotopes have been investigated by level crossing and optical double resonance spectroscopy. The measured hyperfine structure constants yielded the nuclear moments $$\begin{gathered} \mu _I (^{84} Rb) = - 1.296(11)\mu _K Q(^{83} Rb) = + 0.27(5) \cdot 10^{ - 24} cm^2 \hfill \\ Q(^{84} Rb) = + 0.005(13) \cdot 10^{ - 24} cm^2 \hfill \\ Q(^{86} Rb) = + 0.20(3) \cdot 10^{ - 24} cm^2 \hfill \\ \end{gathered} $$ and the hyperfine anomaly84Δ85=+1.7(1.0) · 10?2. The quadrupole moments of83Rb to87Rb can be explained with the unified model of vibrations.  相似文献   

19.
New measurements of the total crosssections of charged-current interactions of muonneutrinos and antineutrinos on isoscalar nuclei have been performed. Data were recorded in an exposure of the CHARM detector in an 160 GeV narrow-band beam. The antineutrino flux was determined from the measurements of the pion and kaon flux, and independently from the muon flux measured in the shield; the two methods are found to agree. The neutrino flux was determined from the muon flux ratio forv μ and \(\bar v_\mu \) runs which was normalized to the antineutrino flux. The cross-section slopes thus determined are $$\begin{gathered} \sigma _T^{\bar v} /E = (0.335 \pm 0.004(stat) \hfill \\ \pm 0.010(syst)).10^{ - 38} cm^2 /(GeV \cdot nucleon) \hfill \\ \sigma _T^v /E = (0.686 \pm 0.002(stat) \hfill \\ \pm 0.020(syst)).10^{ - 38} cm^2 /(GeV \cdot nucleon) \hfill \\ \end{gathered} $$ The momentum sum of the quarks in the nucleon and the ratio of sea quark to total quark momentum are derived from the measurements.  相似文献   

20.
Neutron-deficient osmium and rhenium isotopes were produced by bombarding an enriched144Sm target with beams of27Al and28Si. Previously reported decay data concerning168,169,170Os were confirmed. Three newα groups, observed in the144Sm+27Al reaction, were assigned to the decay of166,167,168Re based on excitation functions,α-energy systematics and theoretical half-life predictions. Their decay properties are: $$\begin{gathered} {}^{166}\operatorname{Re} , E_\alpha = 5,372 (10) keV, T_{1/2} = 2.8 (3) s; \hfill \\ {}^{167}\operatorname{Re} , E_\alpha = 5,136 (8) keV, T_{1/2} = 6.1 (2) s and \hfill \\ {}^{168}\operatorname{Re} , E_\alpha = 4,894 (10) keV, T_{1/2} = 6.9 (8) s. \hfill \\ \end{gathered}$$ It is proposed that twoα groups, observed in the144Sm+28Si reaction, originate from isomeric states in168,169Re. Our measured data for the isomeric states are: $$\begin{gathered} {}^{168m}\operatorname{Re} , E_\alpha = 5,250 (10) keV, T_{1/2} = 6.6 (15) s and \hfill \\ {}^{169m}\operatorname{Re} , E_\alpha = 5,050 (10) keV, T_{1/2} = 12.9 (11) s. \hfill \\ \end{gathered} $$   相似文献   

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