New limits for the exotic exchange reaction π−p → K+Σ− at 5 and 8 GeV

Measurement of the exotic exchange reaction π^?p → K⁺Σ^? has been performed at 5 and 8 GeV, in the ?0.015 to ?0.13 and ?0.009 to ?0.15 (GeV/c)² range of t repectively. We give the value near t = 0 of the differential cross section at 5 GeV, 21_?21⁺⁷⁶ nb/(GeV/c)², and an upper limit (< 37 nb/GeV/c)²) at 8 GeV. As a check the measured differential cross section is given at both energies for the reaction π⁺p → K⁺Σ⁺ in the same range of t.     

ESR aspects of the Mn2+−Cu2+ coupled pair

Recent ESR experimental data on Mn²⁺?Cu²⁺ pairs, obtained by doping with manganese the dimeric Cu (pyridine N-oxide) Cl₂·.H₂O complex, are interpreted by means of a strong isotropic exchange model. Theg values of the pair and the hyperfine constants at the manganese and copper nuclei, for the observed effective spin S = 2, are given by the relations

$\text{g =}\text{7}\text{6}\text{g}{}_{\mathrm{Mn}}\text{?}\text{1}\text{6}\text{g}{}_{\mathrm{Cu}}$

,

$\text{A}\text{?}{}_{\mathrm{Mn}}\text{=}\text{7}\text{6}\text{A}{}_{\mathrm{Mn}}\text{,}\text{A}\text{?}{}_{\mathrm{Cu}}\text{= ?}\text{1}\text{6}\text{A}{}_{\mathrm{Cu}}$

, where g_Mn, g_Cu,A_Mn and A_Cu are the characteristic single-ion values for the quoted constants. The antiferromagnetic coupling between the Mn²⁺ spin $\text{(}\text{5}\text{2}\text{)}$ and the Cu²⁺ spin $\text{(}\text{1}\text{2}\text{)}$ is responsible for the observed g values, all measurably lower than the free electron value. Also to be noted are the enhancement of the hyperfine constant at the manganese nucleus, and the curious change of sign for that at the copper nucleus.     

A study of the reactions π+p→ K+∑+ and K−p→π−∑+ at 10 GeV/c

For the first time, the reactions π⁺p→K⁺∑⁺ and K^?p→π^?∑⁺ have been studied in the same apparatus. This has been done at an adequately high momentum (10.1 GeV/c) to allow a check of the prediction of exchange degeneracy, that the differential cross sections should be converging at high energy. We have measured the cross section for momentum transfers t between t_min and t = ?0.3 (GeV/c)². We find that for both reactions the differential cross section shows an exponential fall, with no deviations right in to t =t_min (where some other experiments have shown a dip in the cross section). Furthermore, we find the magnitude of the differential cross sections to be closely similar at t = 0, with a ratio

$\text{R=}\text{(}\text{d}\text{σ}\text{d}\text{t)}{}_{\mathrm{t=0}}\text{(}\text{K}{}^{\mathrm{?}}\text{p}\text{→π}{}^{\mathrm{?}}\text{∑}{}^{\mathrm{+}}\text{)}\text{(}\text{d}\text{σ}\text{d}\text{t)}{}_{\mathrm{t=0}}\text{(π}{}^{\mathrm{+}}\text{p}\text{→}\text{K}{}^{\mathrm{+}}\text{∑}{}^{\mathrm{+}}$

However, the slope for the positive reaction is about 19% steeper than that for the negative reaction.     

Laser spectroscopy of CaBr: A2Π-X2Σ+ and B2Σ+-X2Σ+ systems

Laser excitation spectra have been recorded for Ca⁷⁹Br and Ca⁸¹Br in the spectral region 600–630 nm. The use of a 1-m monochromator as a narrow band pass filter (1–2 cm^?1) has allowed rotational analysis of the 0-0, 1-1, and 2-2 bands of the B²Σ⁺ - X²Σ⁺ transition and the 0-0 and 1-1 bands of the A²Π - X²Σ⁺ transition. A few additional lines of the 0-1, 1-2, 1-0, and 2-1 bands of the B-X system were used to obtain band origins for vibrational analysis. The main constants for Ca⁷⁹Br are (in cm^?1):

     

6.

Vibration-rotation and deperturbation analysis of A²Π-X²Σ⁺ and B²Σ⁺-X²Σ⁺ systems of the CaI molecule     

David E Reisner  Peter F Bernath  R.W Field 《Journal of Molecular Spectroscopy》1981,89(1):107-124

Doppler-limited laser excitation spectroscopy employing narrow-band fluorescence detection was used to obtain a rotational and vibrational analysis in the (0, 0) and (1, 1) bands of the A²Π-X²Σ⁺ system and the (4, 2) (3, 1), (0, 0), (0, 1), (1, 2), (2, 3), and (3, 4) bands of the B²Σ⁺-X²Σ⁺ system of CaI. The A and B states are deperturbed to obtain spectroscopic constants and Franck-Condon factors. Deperturbation was necessary because of the small separation of the A and B states relative to the A ～ B interaction strength and the A²Π spin-orbit splitting. The main deperturbed constants (in cm^?1) are

	$\text{X}{}^2\text{Σ}{}^{\mathrm{+}}$	$\text{A}{}^2\text{Π}$	$\text{B}{}^2\text{Σ}{}^{\mathrm{+}}$
$\text{T}{}_{\mathrm{e}}$	0	15 958.41 (10)	16 383.137 (6)
$\text{ω}{}_{\mathrm{e}}$	285.732 (9)	288.56 (20)	285.747 (9)
$\text{ω}{}_{\mathrm{e}}\text{χ}{}_{\mathrm{e}}$	0.840 (4)	—	0.954 (4)
$\text{B}{}_{\mathrm{e}}$	0.094466141 (30)	0.0957343 (20)	0.0965151 (20)
$\text{α}{}_{\mathrm{e}}$	0.000403551 (40)	0.0004327 (20)	0.0004483 (15)
$\text{γ}{}_{\mathrm{e}}$ (spin-rot.)	0.00301484 (50)	—	0.068767 (79)
$\text{P}{}_{\mathrm{e}}$	—	?0.066834 (64)	—
$\text{A}{}_{\mathrm{e}}$	—	59.175 (1)	—

     

7.

Energy spectra and energy correlations in the decayH→ZZ→μ+μ−μ+μ−     

Torsten Arens  L. M. Sehgal 《Zeitschrift fur Physik C Particles and Fields》1995,66(1-2):89-94

It is shown that in the sequential decay $H \to ZZ \to (f_1 \bar f_1 ) + (f_2 \bar f_2 )$ , the energy distribution of the final state particles provides a simple and powerful test of theHZZ vertex. For a standard Higgs boson, the energy spectrum of any final fermion, in the rest frame ofH, is predicted to be dΓ/dx～1+β⁴?2(x?1)², with $\beta = \sqrt {1 - 4m_Z^2 /m_H^2 } $ and 1?β≤x=4E/m _H ≤1+β. By contrast, the spectrum for a pseudoscalar Higgs is dΓ/dx～β²+(x?1)². There are characteristic energy correlations betweenf ₁ andf ₂ and betweenf ₁ andf ₂. These considerations are applied to the “gold-plated” reactionH→ZZ→μ⁺μ^?μ⁺μ^?, including possible effects ofCP-violation in theHZZ coupling. Our formalism also yields the energy spectra and correlations of leptons in the decay $H \to W^ + W^ - \to l^ + v_l l^ - \bar v_l $ .     

8.

Perturbations in the A¹Π-X¹Σ⁺ system of the BeO molecule     

H. Lavendy  B. Pouilly  J.M. Robbe 《Journal of Molecular Spectroscopy》1984,103(2):379-407

All perturbations observed by Lagerqvist (Thesis, University of Stockholm, 1948) in the A¹Π-X¹Σ⁺ transition have been assigned to a³Π₂, a³Π₁, and X¹Σ⁺ states. Vibrational and rotational constants of the a³Π state as well as electronic parameters for A ～ X, A ～ a, and a ～ X interactions have been determined.

	$\text{X}{}^2\text{Σ}{}^{\mathrm{+}}$	$\text{A}{}^2\text{Π}$	$\text{B}{}^2\text{Σ}{}^{\mathrm{+}}$
$\text{T}{}_{\mathrm{e}}$	0	15 624.67(5)	15 700.52(12)
$\text{ω}{}_{\mathrm{e}}$	238.7496(33)	241.19(7)	242.63(17)
$\text{ω}{}_{\mathrm{e}}\text{χ}{}_{\mathrm{e}}$	0.62789(64)	0.53(5) (Pekeris)	1.17(12) (Pekeris)
$\text{B}{}_{\mathrm{e}}$	0.0693254(84)	0.070460(14)	0.071572(22)
$\text{α}{}_{\mathrm{e}}\text{× 10}{}^4$	2.640(35)	2.15(10)	3.95(2)
$\text{A}{}_{\mathrm{e}}$	—	45.8968(52)	—
$\text{R}{}_{\mathrm{e}}\text{(}\text{A}\text{?}\text{)}$	2.8286(2)	2.8057(3)	2.7839(4)

     

9.

Optical-optical double-resonance spectroscopy of BaF: The E²Σ⁺ and F²Π states     

Precila C.F Ip  Peter F Bernath  Robert W Field 《Journal of Molecular Spectroscopy》1981,89(1):53-61

Sub-Doppler optical-optical double-resonance excitation spectra of BaF were recorded using two single-mode cw dye lasers. In the 30 000-cm^?1 region, the electronic states observed were E²Σ⁺ and F²Π. The latter had been previously assigned as the “F²Σ⁺” state by Fowler [Phys. Rev.59, 645–652 (1941)]. The (3, 0) and (4, 0) bands of the E²Σ⁺-B²Σ⁺ transition and the (1, 0) and (2, 0) bands of the F²Π-B²Σ⁺ transition were rotationally analyzed. The molecular constants suggest inferences about the dominant atomic orbital character of the Rydberg molecular orbitals responsible for the E²Σ⁺ and F²Π electronic states. A new electronic state, the $\text{E′}{}^2\text{Π}$, is predicted. The molecular parameters obtained (in cm^?1, 1σ uncertainty in parentheses) are

	Reciprocal centimeters
	Te	ωe	ωexe	Be	αe	re (Å)
a3Π	8574	1132	8.4	1.3675	?0.0168	1.4623

     

10.

Four-jet production in e⁺e⁻-annihilation     

A. Ali  J.G. Körner  Z. Kunszt  J. Willrodt  G. Kramer  G. Schierholz  E. Pietarinen 《Physics letters. [Part B]》1979,82(2):285-288

We investigate the four-jet production processes $e^{+}{e}^{?}\to q\overline{q}ggand{e}^{+}{e}^{?}\to q\overline{q}q\overline{q}$ in lowest order QCD perturbation theory. We estimate that four-jet events should be detectable at a rate of about 5% at the highest PETRA energy. The acoplanarity distribution is calculated and compared to nonperturbative effects.     

11.

The A²Π-X²Π system of the SbO molecule     

Walter J Balfour  Ram S Ram 《Journal of Molecular Spectroscopy》1984,105(1):246-259

The emission spectrum of the A²Π-X²Π system of the SbO molecule has been photographed under high resolution, and the rotational structure in eight bands of the ${}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{-}{}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ component, involving v′ = 0–2 and v″ = 1–4, has been analyzed for both isotopic molecules ¹²¹SbO and ¹²³SbO. The observed rotational lines of the corresponding ${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{-}{}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ component are broad, with a width of about 0.2 cm^?1 varying little with J. It is suggested that these broad lines represent unresolved components arising from magnetic hyperfine interaction with ¹²¹Sb or ¹²³Sb nuclei. Isotopic shift observations contradict earlier vibrational assignments in the ${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{-}{}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ subsystem and indicate that the A state is inverted in agreement with expectations from related systems. The principal molecular constants (in cm^?1) obtained for ¹²¹SbO are

	$\text{v′}{}_{\mathrm{E}}$	$\text{E}{}^2\text{Σ}{}^{\mathrm{+}}$	$\text{v′}{}_{\mathrm{F}}$	$\text{F}{}^2\text{Π}$
$\text{T}{}_{\mathrm{v\prime 0}}$	3	29 767.32(1)	1	29 997.29(1)
$\text{Δ}\text{G}{}_{\mathrm{<mtext>v\prime \; +\; </mtext><mtext>1</mtext><mtext>2</mtext>}}$	3	522.841(27)	1	522.553(2)
$\text{B}{}_{\mathrm{e}}$		0.22990(22)		0.22931(8)
$\text{α}{}_{\mathrm{e}}$		0.00113(14)		0.00108(2)
$\text{A}{}_{\mathrm{v\prime }}$			1	56.9840(12)
$\text{p}{}_{\mathrm{v\prime }}$			1	?0.02426(6)
$\text{γ}{}_{\mathrm{v\prime }}$	3	?0.17367(46)

     

12.

Determination of the branching ratio ofρ 0→+μ− in the coherent dissociation π−→μ+μ−π− and π−→π+π−π−     

Yu. M. Antipov  V. A. Batarin  V. A. Bessubov  M. S. Bilenky  N. P. Budanov  D. S. Denisov  O. V. Eroshin  P. L. Frabetti  Yu. P. Gorin  Yu. A. Gornushkin  V. G. Kartasheva  P. A. Kulinich  A. A. Nosdrin  A. G. Olshevski  F. Palombo  A. I. Petrukhin  R. V. Pirtzkhalava  S. A. Polovnikov  V. N. Roinishvili  D. A. Stoianova  A. V. Vishnevski 《Zeitschrift fur Physik C Particles and Fields》1989,42(2):185-187

In the diffraction dissociation of π^? into μ⁺μ^?π^? on a Cu nucleus at 50 GeV/c, the cross section \(\sigma _{\mu ^ + \mu ^ - \pi ^ - } \) for the 1⁺S(ρ⁰π) wave was measured. The branching ratio of ρ⁰→μ⁺μ^? could be calculated from the ratio of this and the corresponding cross sections in the diffraction dissociation of π^? into π⁺π^?π^?. The obtained value \(BR_{\rho ^0 \to \mu ^ + \mu ^ - } = (4.6 \pm 0.2_{stat^ \pm } \pm 0.2_{syst} )10^{ - 5} \) is in good agreement with the branching ratio \(BR_{\rho ^0 \to e^ + e^ - } \) , as expected ifeμ universality holds.     

13.

The Ångström (B¹Σ⁺-A¹Π) band system of ¹³C¹⁸O     

C.V.V. Prasad  G.L. Bhale  S. Paddi Reddy 《Journal of Molecular Spectroscopy》1984,104(1):165-173

The Ångström (B¹Σ⁺-A¹Π) band system of the ¹³C¹⁸O molecule, excited in a hollow-cathode discharge tube, has been observed in the region 4100–6500Å. All the eight bands of the system, viz., 1-0, 1-1, 0-0, 0–1, 0–2, 0–3, 0–4, and 0–5 were photographed under high resolution and their rotational analyses, except for the apparently complex 0-0 band, have been carried out. Vibrational constants of the B and A states have been obtained from the band origin data. The derived molecular constants (in cm^?1, except r_e in Å) of the B-A system of¹³C¹⁸O are

State	$\text{T}{}_{\mathrm{e}}$	$\text{ω}{}_{\mathrm{e}}$	$\text{ω}{}_{\mathrm{e}}\text{χ}{}_{\mathrm{e}}$	$\text{B}{}_{\mathrm{e}}$	$\text{10}{}^3\text{α}{}_{\mathrm{e}}$	$\text{10}{}^7\text{D}{}_{\mathrm{e}}$
$\text{X}{}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$	0	818.7	4.2	—	—	—
$\text{X}{}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$	x ≈ 2272	814.1	4.3	0.35920	2.38	2.8
$\text{A}{}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$	21 467.4	565.8	2.9	—	—	—
$\text{A}{}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$	x + 18 521.7	570.4	2.6	0.28856	1.82	2.9

     

14.

B_s⁰ → μ⁺μ^? in LHCb     

D. Martinez Santos 《Physics of Atomic Nuclei》2009,72(9):1548-1552

Due to its sensitivity to New Physics contributions, the branching ratio of the very rare decay B _s ⁰ → μ ⁺ μ ⁻ is one of the most interesting measurements using the first data from the LHC accelerator. The analysis strategy for the study of this channel in the LHCb experiment is presented, as well as a review of the potential of the experiment in such study, using the latest simulations. With four months of nominal data taking, any enhancement from the Standard Model prediction can be excluded.     

15.

Event generators for η/η' rare decays into π⁺π^-l⁺l^- and e⁺e^-μ⁺μ^-     

张振宇  秦丽清 《中国物理 C》2012,36(10)

Study of the rare and forbidden decays of η/η' offers a sensitive probe to test fundamental symmetries of quantum chromodynamics and search for new physics beyond the Standard Model. To study the rare decays of η/η' to π⁺π^-e⁺e^-, π⁺π^-μ⁺μ^- and e⁺e^-μ⁺μ^- at the BESⅢ detector, we developed several event generators based on the vector meson dominant model with finite-width corrections and the pseudoscalar mesons mixing theory. The various distributions from event generators are in good agreement with the theoretical predictions, which indicates that the event generators work very well after implemention in the BESⅢ Monte Carlo simulation package. In the BESⅢ physics analysis, the performance of the event generators will be improved in accordance with the distributions of different variables of η/η' from data and the improvement on the theoretical calculations.     

16.

Smilansky–Solomyak model with a δ^′-interaction     

Pavel Exner  Jiří Lipovský 《Physics letters. A》2018,382(18):1207-1213

We investigate a strongly singular version of the model of irreversible dynamics proposed by Smilansky and Solomyak in which the interaction responsible for an abrupt change of the spectrum is of ${\delta }^{\prime }$ type. We determine the spectrum in both the subcritical and supercritical regimes and discuss its character as well as its asymptotic properties of the discrete spectrum in terms of the coupling constant.     

17.

A Study of the Processes of e⁺e^－→e⁺e^－,μ⁺μ^－ at Large Angle and Measured Luminosities          下载免费PDF全文

BES Collaboration 《中国物理C(英文版)》1997,21(2):97-103

Using the BES data collected at √S=4.03GeV.the QED processes of e⁺e^－→e⁺e^－,μ⁺μ^－ have been studied. Our measurements agree with the QED prediction,and luminosities obtained from these two final states are compatible at a level of 4%.The total integrated luminosity of 23.1pb^－1 was given for all data collected at this energy region from the calculation.     

18.

Constraints on the new particle in Σ+→pμ+μ−     

《Physics letters. [Part B]》2006,632(2-3):215-218

     

19.

最轻的中性TC介子P⁰和μ⁺μ^－对撞机     

岳崇兴  鲁公儒  李建涛 《中国物理 C》2001,25(12):1140-1146

在顶色辅助的多标度人工色(TOPCMTC)模型框架下,讨论了最轻的中性TC介子P⁰在μ⁺μ^－对撞机(FMC)上的s道共振产生.计算结果表明:其有效产生截面非常大,至少比标准模型中的Higgs粒子h⁰的产生截面大一个量级.因此,FMC可以用来探测TC介子的存在进而检验人工色理论.     

20.

光生相对论的（μ⁺μ^-）,（e⁺e^-）仲原子     

何炬  张肇西  何祚庥 《中国物理 C》1979,3(1)

本文应用复合场论微扰展开式和相对论的 B-S 近似波函数,计算了类似于 Primakoff 效应的光生相对论的（e⁺e^-）,（μ⁺μ^-）仲原子的过程.结果与通常点模型的计算结果不同,这里多得出了一个新的形状因子.这表明在通常的Primakoff 效应中也将存在类似的修正.     

	ωe	ωeXe	Be	αe	re(Å)
B1∑+	2012.97	12.95	1.7805(4)	0.0219(6)	1.1198
A1II	1444.49	15.73	1.4660(5)	0.0201(1)	1.2350

Vibration-rotation and deperturbation analysis of A2Π-X2Σ+ and B2Σ+-X2Σ+ systems of the CaI molecule

Doppler-limited laser excitation spectroscopy employing narrow-band fluorescence detection was used to obtain a rotational and vibrational analysis in the (0, 0) and (1, 1) bands of the A²Π-X²Σ⁺ system and the (4, 2) (3, 1), (0, 0), (0, 1), (1, 2), (2, 3), and (3, 4) bands of the B²Σ⁺-X²Σ⁺ system of CaI. The A and B states are deperturbed to obtain spectroscopic constants and Franck-Condon factors. Deperturbation was necessary because of the small separation of the A and B states relative to the A ～ B interaction strength and the A²Π spin-orbit splitting. The main deperturbed constants (in cm^?1) are

Energy spectra and energy correlations in the decayH→ZZ→μ+μ−μ+μ−

It is shown that in the sequential decay $H \to ZZ \to (f_1 \bar f_1 ) + (f_2 \bar f_2 )$ , the energy distribution of the final state particles provides a simple and powerful test of theHZZ vertex. For a standard Higgs boson, the energy spectrum of any final fermion, in the rest frame ofH, is predicted to be dΓ/dx～1+β⁴?2(x?1)², with $\beta = \sqrt {1 - 4m_Z^2 /m_H^2 } $ and 1?β≤x=4E/m _H ≤1+β. By contrast, the spectrum for a pseudoscalar Higgs is dΓ/dx～β²+(x?1)². There are characteristic energy correlations betweenf ₁ andf ₂ and betweenf ₁ andf ₂. These considerations are applied to the “gold-plated” reactionH→ZZ→μ⁺μ^?μ⁺μ^?, including possible effects ofCP-violation in theHZZ coupling. Our formalism also yields the energy spectra and correlations of leptons in the decay $H \to W^ + W^ - \to l^ + v_l l^ - \bar v_l $ .     

Perturbations in the A1Π-X1Σ+ system of the BeO molecule

All perturbations observed by Lagerqvist (Thesis, University of Stockholm, 1948) in the A¹Π-X¹Σ⁺ transition have been assigned to a³Π₂, a³Π₁, and X¹Σ⁺ states. Vibrational and rotational constants of the a³Π state as well as electronic parameters for A ～ X, A ～ a, and a ～ X interactions have been determined.

Optical-optical double-resonance spectroscopy of BaF: The E2Σ+ and F2Π states

Sub-Doppler optical-optical double-resonance excitation spectra of BaF were recorded using two single-mode cw dye lasers. In the 30 000-cm^?1 region, the electronic states observed were E²Σ⁺ and F²Π. The latter had been previously assigned as the “F²Σ⁺” state by Fowler [Phys. Rev.59, 645–652 (1941)]. The (3, 0) and (4, 0) bands of the E²Σ⁺-B²Σ⁺ transition and the (1, 0) and (2, 0) bands of the F²Π-B²Σ⁺ transition were rotationally analyzed. The molecular constants suggest inferences about the dominant atomic orbital character of the Rydberg molecular orbitals responsible for the E²Σ⁺ and F²Π electronic states. A new electronic state, the $\text{E′}{}^2\text{Π}$, is predicted. The molecular parameters obtained (in cm^?1, 1σ uncertainty in parentheses) are

Four-jet production in e+e−-annihilation

We investigate the four-jet production processes $e^{+}{e}^{?}\to q\overline{q}ggand{e}^{+}{e}^{?}\to q\overline{q}q\overline{q}$ in lowest order QCD perturbation theory. We estimate that four-jet events should be detectable at a rate of about 5% at the highest PETRA energy. The acoplanarity distribution is calculated and compared to nonperturbative effects.     

The A2Π-X2Π system of the SbO molecule

The emission spectrum of the A²Π-X²Π system of the SbO molecule has been photographed under high resolution, and the rotational structure in eight bands of the ${}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{-}{}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ component, involving v′ = 0–2 and v″ = 1–4, has been analyzed for both isotopic molecules ¹²¹SbO and ¹²³SbO. The observed rotational lines of the corresponding ${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{-}{}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ component are broad, with a width of about 0.2 cm^?1 varying little with J. It is suggested that these broad lines represent unresolved components arising from magnetic hyperfine interaction with ¹²¹Sb or ¹²³Sb nuclei. Isotopic shift observations contradict earlier vibrational assignments in the ${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{-}{}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ subsystem and indicate that the A state is inverted in agreement with expectations from related systems. The principal molecular constants (in cm^?1) obtained for ¹²¹SbO are

Determination of the branching ratio ofρ 0→+μ− in the coherent dissociation π−→μ+μ−π− and π−→π+π−π−

In the diffraction dissociation of π^? into μ⁺μ^?π^? on a Cu nucleus at 50 GeV/c, the cross section \(\sigma _{\mu ^ + \mu ^ - \pi ^ - } \) for the 1⁺S(ρ⁰π) wave was measured. The branching ratio of ρ⁰→μ⁺μ^? could be calculated from the ratio of this and the corresponding cross sections in the diffraction dissociation of π^? into π⁺π^?π^?. The obtained value \(BR_{\rho ^0 \to \mu ^ + \mu ^ - } = (4.6 \pm 0.2_{stat^ \pm } \pm 0.2_{syst} )10^{ - 5} \) is in good agreement with the branching ratio \(BR_{\rho ^0 \to e^ + e^ - } \) , as expected ifeμ universality holds.     

The Ångström (B1Σ+-A1Π) band system of 13C18O

The Ångström (B¹Σ⁺-A¹Π) band system of the ¹³C¹⁸O molecule, excited in a hollow-cathode discharge tube, has been observed in the region 4100–6500Å. All the eight bands of the system, viz., 1-0, 1-1, 0-0, 0–1, 0–2, 0–3, 0–4, and 0–5 were photographed under high resolution and their rotational analyses, except for the apparently complex 0-0 band, have been carried out. Vibrational constants of the B and A states have been obtained from the band origin data. The derived molecular constants (in cm^?1, except r_e in Å) of the B-A system of¹³C¹⁸O are

Bs0 → μ+μ? in LHCb

Due to its sensitivity to New Physics contributions, the branching ratio of the very rare decay B _s ⁰ → μ ⁺ μ ⁻ is one of the most interesting measurements using the first data from the LHC accelerator. The analysis strategy for the study of this channel in the LHCb experiment is presented, as well as a review of the potential of the experiment in such study, using the latest simulations. With four months of nominal data taking, any enhancement from the Standard Model prediction can be excluded.     

Event generators for η/η' rare decays into π+π-l+l- and e+e-μ+μ-

Study of the rare and forbidden decays of η/η' offers a sensitive probe to test fundamental symmetries of quantum chromodynamics and search for new physics beyond the Standard Model. To study the rare decays of η/η' to π⁺π^-e⁺e^-, π⁺π^-μ⁺μ^- and e⁺e^-μ⁺μ^- at the BESⅢ detector, we developed several event generators based on the vector meson dominant model with finite-width corrections and the pseudoscalar mesons mixing theory. The various distributions from event generators are in good agreement with the theoretical predictions, which indicates that the event generators work very well after implemention in the BESⅢ Monte Carlo simulation package. In the BESⅢ physics analysis, the performance of the event generators will be improved in accordance with the distributions of different variables of η/η' from data and the improvement on the theoretical calculations.     

Smilansky–Solomyak model with a δ′-interaction

We investigate a strongly singular version of the model of irreversible dynamics proposed by Smilansky and Solomyak in which the interaction responsible for an abrupt change of the spectrum is of ${\delta }^{\prime }$ type. We determine the spectrum in both the subcritical and supercritical regimes and discuss its character as well as its asymptotic properties of the discrete spectrum in terms of the coupling constant.     

A Study of the Processes of e+e－→e+e－,μ+μ－ at Large Angle and Measured Luminosities

Using the BES data collected at √S=4.03GeV.the QED processes of e⁺e^－→e⁺e^－,μ⁺μ^－ have been studied. Our measurements agree with the QED prediction,and luminosities obtained from these two final states are compatible at a level of 4%.The total integrated luminosity of 23.1pb^－1 was given for all data collected at this energy region from the calculation.     

最轻的中性TC介子P0和μ+μ－对撞机

在顶色辅助的多标度人工色(TOPCMTC)模型框架下,讨论了最轻的中性TC介子P⁰在μ⁺μ^－对撞机(FMC)上的s道共振产生.计算结果表明:其有效产生截面非常大,至少比标准模型中的Higgs粒子h⁰的产生截面大一个量级.因此,FMC可以用来探测TC介子的存在进而检验人工色理论.     

光生相对论的（μ+μ-）,（e+e-）仲原子

本文应用复合场论微扰展开式和相对论的 B-S 近似波函数,计算了类似于 Primakoff 效应的光生相对论的（e⁺e^-）,（μ⁺μ^-）仲原子的过程.结果与通常点模型的计算结果不同,这里多得出了一个新的形状因子.这表明在通常的Primakoff 效应中也将存在类似的修正.