Measurement of the νμ and νμ nucleon charged-current total cross sections,and the ratio of νμ neutron to νμ proton charged-current total cross sections

The total ν_μ and $\text{ν}{}_{\mathrm{\mu }}$ nucleon charged-current cross sections have been measured in BEBC filled with deuterium and exposed to the wide-band neutrino and antineutrino beams at the CERN-SPS. Assuming a linear energy dependence for the cross sections, σ = aE(?_ν, we obtained the coefficients , where the quoted error is mainly systematic. The ratio of the cross sections is $\text{σ}{}_{\mathrm{<mtext>\nu </mtext><mtext>N</mtext>}}\text{/σ}{}_{\mathrm{<mtext>\nu </mtext><mtext>N</mtext>}}\text{= 0.53 ± 0.03}$.We also determined the ratio of the charged-current cross section for neutrino interactions on neutrons and protons R = σ_νn/σ_νp = 2.10 ± 0.08 (statistical) ±0.22 (sysetmatic). The dependence of R on the variables x, y and E_ν is discussed.     

A search at high energies for antineutrino-electron elastic scattering

We have searched for candidates for the weak neutral leptonic current reaction $\text{ν}{}_{\mathrm{\mu }}\text{+}\text{e}{}^{\mathrm{?}}\text{→}\text{ν}{}_{\mathrm{\mu }}\text{+}\text{e}{}^{\mathrm{?}}$ in the Fermilab 15 ft bubble chamber filled with a heavy neon-hydrogen mix. Based on zero observed events of this type we find the 90% confidence level upper limit for the rate for this reaction relative to the total antineutrino charged current rate to be 3.9 × 10^?4 and, in the Weinberg-Salam model, sin²θ_W ? 0.37.     

An experimental investigation of the radiative structure decay K+ → e+υγ

The decay K⁺ → e⁺υγ has been investigated. For the structure-dependent part with positive γ-helicity (SD₊) the branching ratio $\text{Γ(}\text{SD}{}_{\mathrm{+}}\text{)}\text{Γ(}\text{K}{}_{\mathrm{\mu 2}}\text{) = (2.33 ± 0.42) × 10}{}^{\mathrm{?5}}$ is obtained from 51 ± 3 events observed in the kinematical region E_e ? 235 MeV, E_γ > 48 MeV and θ_eγ > 140°. For the corresponding part with negative γ-helicity we obtain an upper limit Γ(SD_?)/Γ(SD₊) < 11 (90% CL) from the sample of electrons with energies 220 MeV ? E_e < 230 MeV and with no γ in the backward direction. This upper limit implies that the ratio of structure-dependent axial vector amplitudes lies outside the region $\text{?1.8 < a}{}_{\mathrm{<mtext>K</mtext>}}\text{υ}{}_{\mathrm{<mtext>K</mtext>}}\text{< ?0.54}$.For the decay $\text{K}{}^{\mathrm{+}}\text{→}\text{e}{}^{\mathrm{+}}\text{νν}\text{ν}$ the limit $\text{Γ(}\text{K}{}^{\mathrm{+}}\text{→}\text{e}{}^{\mathrm{+}}\text{νν}\text{ν}\text{)/Γ(}\text{K}{}_{\mathrm{e2}}\text{) < 3.8}$ 90% confidence level) was found.     

A search for the decay μ → e γ

We report on the final analysis of a search for the decay μ⁺→e⁺γ performed at SIN. No evidence for the existence of the process has been found. An upper limit for the branching ratio of 1.0 × 10^?9 (90% confidence) is presented. The measured positron-photon energy distributions are completely described by the decay $\text{μ}{}^{\mathrm{+}}\text{→}\text{e}{}^{\mathrm{+}}\text{ν}{}_{\mathrm{<mtext>e</mtext>}}\text{ν}{}_{\mathrm{\mu }}\text{γ}$ and accidental coincidences.     

Experimental limits on the mass and decay lifetime of νμ

The nonobservation of photon-induced e⁺e^? pairs pointing in the neutrino beam direction in large bubble chambers would allow one to set an upper limit on the product m_νμλ^CM for muon-type neutrinos, where m_νμ is the mass and λ^CM is the intrinsic partial decay width in sec^?1 for ν_μ→γ+X. In the theory of Eliezer and Ross where , this implies an upper limit on m_νμ considerably smaller than the present upper limit, and a large lower limit on the lifetime τ_νμ.     

Positron production by muon neutrinos BEBC filled with a neon-hydrogen mixture

For e⁺ energy > 0.3 GeV and 10 GeV < visible energy < 100 GeV we find that: (i) $\text{? = (v}{}_{\mathrm{\mu }}\text{+}\text{Ne}\text{→ μ}{}^{\mathrm{?}}\text{e}{}^{\mathrm{+}}\text{)/(v}{}_{\mathrm{\mu }}\text{+}\text{Ne}\text{→ μ}{}^{\mathrm{?}}\text{) = (0.41 ± 0.15)\%}$; (ii) 1.2 ± 0.5 neutral strange particles are produced per μ^?e⁺ event; (iii) the lifetime of possible positron-parent particles is < 3 × 10^?10 s (90% C.L.); (iv) the cross section for direct e⁺ production via the neutral current is < 0.2 times that via the charged current (90% C.L.); (v) the cross section for producing heavy leptons, L⁺, decaying into e⁺ … is < 0.7 × 10^?3 times that for μ^?production, implying M(L⁺) > 10 GeV.     

Coriolis intensity perturbations in the SO2 molecule: Experimental determination of the relative signs of (∂μ∂Qi)

The Coriolis interactions between ν₁ and ν₃, and between ν₂ and ν₃ in SO₂ have been analyzed to obtain the signs of the products $\text{ζ}{}_{3.1}{}^{\mathrm{c}}\text{(}\text{?μ}{}^{\mathrm{a}}\text{?Q}{}_3\text{)(}\text{?μ}{}^{\mathrm{b}}\text{?Q}{}_1\text{)}$ and $\text{ζ}{}_{3.2}{}^{\mathrm{c}}\text{(}\text{?μ}{}^{\mathrm{a}}\text{?Q}{}_3\text{)(}\text{?μ}{}^{\mathrm{b}}\text{?Q}{}_2\text{)}$. It has been found that both of the signs of these products are positive. Then, relative signs of ($\text{?μ}\text{?Q}{}_1$) have been determined using the calculated values of the Coriolis zeta constants for the present definition of the normal coordinates. The obtained sign combination of ($\text{?μ}\text{?Q}{}_{\mathrm{i}}$) is ±(+?+), which agrees with the one predicted by the molecular orbital calculations. Using the sign combination (+?+), the polar tensors of S and O atoms were also calculated.     

Charmed meson decays and right-handed currents

In the presence of right-handed currents including $\text{(}\text{c}\text{s}\text{)}{}_{\mathrm{<mtext>R</mtext>}}$, it is emphasized that the dominant parity-violating (-conserving) Hamiltonian for nonleptonic decays of charmed hadrons transforms like $\text{45}\text{+}\text{45}{}^1\text{(}\text{20″ +}\text{84}\text{)}$ of SU(4), and leads to distinctive results especially in D⁺ → K_Sπ⁺, F⁺ → μ⁺ν_μ and D⁰ → K^?e⁺ν_e, etc.     

New upper limit for μ− → e+ conversion

An upper limit for μ^? → e⁺ conversion has been established by searching for specific decay properties of the expected final state nucleus. We obtain $\text{R}{}_{\mathrm{<mtext>coh</mtext>}}\text{= (μ}{}^{\mathrm{?}}\text{+}{}^{127}\text{I →}\text{e}{}^{\mathrm{+}}{}^{127}\text{Sb}{}^1\text{)/(μ}{}^{\mathrm{?}}\text{→ v}{}_{\mathrm{\mu }}\text{) < 3 × 10}{}^{\mathrm{?10}}$ with 90% c.l.     

Inclusive production of Ξ+ and Ξ− in K+ p interactions at 32 GeV/c

The inclusive production of $\text{Ξ}{}^{\mathrm{+}}$ and Ξ^? hyperons is investigated in K⁺ p interactions at 32 GeV/c. The production cross sections, 36.4±9 μb for the $\text{Ξ}{}^{\mathrm{+}}$ and 6.5±3 μb for the Ξ^?, are rising strongly with energy similarly to $\text{Λ}$ and Λ production in K⁺ p interactions. The $\text{Ξ}{}^{\mathrm{+}}$ are produced preferentially in the forward direction in the c.m.s., while the Ξ^? are produced dominantly backwards. The average transverse momenta and 〈p_T〉_Ξ^?=0.58±0.09 GeV/c.     

Analysis of the Raman spectrum of SF6

The Raman active fundamentals ν₁(A1g), ν₂(Eg), ν₅(F2g), and the overtone 2ν₆ of SF₆ have been investigated with a higher resolution and the band origins were estimated to be: ν₁ = 774.53 cm^?1, ν₂ = 643.35 cm^?1, ν₅ = 523.5 cm^?1, and 2ν₆ = 693.8 cm^?1. Raman and infrared data have been combined for estimation of several anharmonicity constants. The ν₆ fundamental frequency is calculated as 347.0 cm^?1. From the analysis of the ν₂ Raman band, the following rotational constants of both the ground and upper states have been calculated:

$\text{B}{}_0\text{= 0.09111 ± 0.00005}\text{cm}{}^{\mathrm{?1}}\text{; D}{}_0\text{= (0.16±0.08)10}{}^{\mathrm{?7}}\text{cm}{}^{\mathrm{?1}}$

;

$\text{B}{}_2\text{= 0.09116 ± 0.00005}\text{cm}{}^{\mathrm{?1}}\text{; D}{}_2\text{= (0.18±0.04)10}{}^{\mathrm{?7}}\text{cm}{}^{\mathrm{?1}}$

.     

Average polarization of 12B in 12C(μ, ν)12B(g.s.) reaction: Helicity of the π-decay muon and nature of the weak coupling

The helicity, h^?, of μ^? in π-decay has been determined as positive (h^??+0.90) from the average polarization, P_av≡〈J_B·s_μ〉, of ¹²B produced in the $\text{μ}{}^{\mathrm{?}}\text{+}{}^{12}\text{C}\text{→ν}{}_{\mathrm{\mu }}\text{+}{}^{12}\text{B}$ reaction. We obtain also dynamical information on μ-capture: (i) the weak magnetism form factor, μ=4.5±1.1, and (ii) the sum of the induced pseudoscalar (g_p) and the 2nd class induced tensor (g_T) couplings versus g_A, ($\text{g}{}_{\mathrm{<mtext>P</mtext>}}\text{+g}{}_{\mathrm{<mtext>T</mtext>}}\text{)}\text{g}{}_{\mathrm{<mtext>A</mtext>}}\text{=7.1±2.7}$. The latter result, adopting the “canonical” value of $\text{g}{}_{\mathrm{<mtext>P</mtext>}}\text{g}{}_{\mathrm{<mtext>A</mtext>}}$, leads to $\text{g}{}_{\mathrm{<mtext>T</mtext>}}\text{g}{}_{\mathrm{<mtext>A</mtext>}}\text{=+1±2.7}$ which is compatible with zero and in strong contradiction with the value ?—6 recently advocated by Kubodera, Delorme and Rho.     

Constraints on the reaction νμ(νμ) + Z → νμ(νμ) + μ− + μ+ + Z in theories with neutral currents

In the presence of neutral lepton currents, the characteristics of the reaction $\text{ν}{}_{\mathrm{\mu }}\text{(}\text{ν}{}_{\mathrm{\mu }}\text{) +}\text{Z}\text{→ ν}{}_{\mathrm{\mu }}\text{(}\text{ν}{}_{\mathrm{\mu }}\text{) + μ}{}^{\mathrm{?}}\text{+ μ}{}^{\mathrm{+}}\text{+}\text{Z}$ are modified from those expected in the conventional V-A theory. We show that in a very general class of intermediate boson theories, the modification produced can be specified entirely in terms of the cross sections for $\text{ν}{}_{\mathrm{\mu }}\text{(}\text{ν}{}_{\mathrm{\mu }}\text{) +}\text{e}{}^{\mathrm{?}}\text{→ ν}{}_{\mathrm{\mu }}\text{(}\text{ν}{}_{\mathrm{\mu }}\text{) +}\text{e}{}^{\mathrm{?}}$. Such a constraint does not necessarily exist in models with four-fermion interaction.     

Measurements of tau decay modes and a precise determination of the mass

The cross sections for e⁺e^? → e⁺(μ⁺ + non showering track + any photons have been measured for cm energies between 3.1 GeV and 5.2 GeV. We observe τ-pair production below the thresholdfor charm production and determine the τ mass to be 1.807 ± 0.020 GeV from a fit to the energy dependence of the cross section. The ration of the leptonic branching ratios B_μ/B_e = 0.92 ± 0.32 is consistent with eμ-universality. The following branching ratios are determined for a V-A coupling: $\text{B(τ → ν}{}_{\mathrm{\tau }}\text{e}\text{ν}\text{) = B(τ → ν}{}_{\mathrm{\tau }}\text{μ}\text{ν}\text{) = 0.182 + 0.028}$. B(τ → ν_τ + charged hadron + any photons) = 0.29 ± 0.11, B(τ → ν_τ + three or more charged hadrons + any photons) = 0.35 ± 0.11.     

Like-sign dimuon events produced in narrow-band neutrino and antineutrino beams

Forty seven events of the type v + Fe → μ^? + μ^? + X and nine events of the type $\text{v}\text{+}\text{Fe}\text{→ μ}{}^{\mathrm{+}}\text{+ μ}{}^{\mathrm{+}}\text{+}\text{X}$ have been observed, and zero events with like-sign muons of the opposite sign. Most of the observed events can be attributed to the background of normal charged current events, in which one of the pions or kaons of the hadron shower decays, and so produces a second muon. The remaining events correspond to rates of the order of (3 ± 2) × 10^?4 of those for charged current events. They may very well be due to the hadronic production of a charm-anticharm pair, with subsequent decay of one member of the pair. The observed rates correspond to charm-anticharm pair production in 0.5–1% of the hadron showers. No evidence can be found for a lepton-cascade origin of the observed events.     

Missing transverse energy events and the standard model

The processes $\text{p+}\text{p}\text{→ W}{}^{\mathrm{\pm }}$, Z⁰+0,1,2 jets are studied in the light of recent observations of events with large missing transverse momentum at the CERN p$\text{p}$ collider. We find that a nontrivial number of such events can arise from the leptonic decays $\text{Z}{}^0\text{→ ν}\text{ν}$ and W^± → ?^±ν where the charged lepton escapes identification. In both cases the number of events with one jet and with two jets are comparable. By correlating these decay modes with those where the leptons are observed we can, in principle, eliminate the theoretical uncertainties inherent in such perturbative QCD calculations.     

Signatures of neutral heavy leptons in neutrino-induced dilepton events

The tentative indication in some experiments of μ^?e⁺ or π^?μ⁺ events with unusual characteristics revives the speculation that neutrino-induced dileptons may contain a weak signal of neutral heavy lepton (L⁰) production. We study the characteristics of dileptons expected from the production of an L⁰ through a current of the form $\text{L}{}^0\text{γ}{}_{\mathrm{\alpha }}\text{(1+γ}{}_5\text{)ν}{}_{\mathrm{\mu }}$. Both quasi-elastic and deep inelastic excitation are investigated and a comparison is made with dileptons of charm origin. As an illustration of a model with a ν_μ→L⁰ transition, we discuss the 2-2 version of the SU(2) × U(1) model and comment on the role of the Higgs particle in such transitions.     

Vibrational spectra and force constants of symmetric tops: High resolution spectra of monoisotopic H3SiCl in the 2200-cm−1 region and rovibrational analysis of the ν1 and ν4 fundamentals

The gas phase infrared spectra of monoisotopic H₃Si³⁵Cl and H₃Si³⁷Cl have been studied in the $\text{ν}{}_1\text{ν}{}_4$ region near 2200 cm^?1 with a resolution of 0.012 and 0.04 cm^?1, respectively, and rotational fine structure for ΔJ = ±1 branches has been resolved. In addition, some information on ν₃ + ν₄ of H₃Si³⁵Cl near 2750 cm^?1 has been obtained. ν₁ and ν₄ are weakly coupled by Coriolis x, y resonance, $\text{B}\text{Ω}{}_{14}\text{ζ}{}_{14}\text{～ 2 × 10}{}^{\mathrm{?3}}\text{cm}{}^{\mathrm{?1}}$, only the upper states K′ = 2, l = 0 and K′ = 1, l = ?1 being substantially affected. Local perturbation due to rotational l(±1, ±1)-type resonance with ν₃ + ν₅⁺¹ + ν₆⁺¹ and ν₃ + ν₅⁺¹ + ν₆^?1 is revealed in the ΔK = +1 and ?1 branches, respectively. From a fit of the experimental line positions, standard deviations of 1.4 and 3.8 × 10^?3 cm^?1, respectively, to a model with five interacting levels conventional excited state parameters and interaction constants have been obtained. In $\text{H}{}_3\text{Si}{}^{35}\text{Cl}\text{H}{}_3\text{Si}{}^{37}\text{Cl}$ the fundamentals are ν₁, $\text{2201.94380(15)}\text{2201.9345(7)}$ and ν₄, $\text{2209.63862(8)}\text{2209.6254(2)}\text{cm}{}^{\mathrm{?1}}$, respectively. Q branches of the “hot” band (ν₃ + ν₄) ? ν₃ and of ν₄ of the ²⁹Si and ³⁰Si species have been detected.     

Flavor changing neutral currents and multileptons in e+e- and vμN,vμN

New quarks and new flavor-changing neutral currents give multiple lepton plus hadron final states in e⁺e^-, $\text{v}{}_{\mathrm{\mu }}\text{N,}\text{v}{}_{\mathrm{\mu }}\text{N}$. We observe that (i) e⁺e^- is a favored place to search for their effects through inclusive ratios σ(e⁺e^-+x:σ (μ⁺μ^- +x): σ(e±μ±+x) and same sign leptons e±e±+x, μ±μ±+x,e±μ±+x. Above a new flavor threshold four charged lrpton final states may become important. (ii) Trilepton final states in $\text{v}{}_{\mathrm{\mu }}\text{N,}\text{v}{}_{\mathrm{\mu }}\text{N}$ are not sensitive to the presence of flavor-changing neutral currents. Much more sensitive are the processes $\text{v}{}_{\mathrm{\mu }}\text{N}$ are ⁺e^-+βand (for charm changing neutral currents) $\text{v}{}_{\mathrm{\mu }}\text{N→e}{}^{\mathrm{+}}\text{β}$.     

Production and signature of intermediate vector bosons

The front-back asymmetry of outgoing muons in the inclusive reaction $\text{p}\text{p}\text{→ Z(→ μ}{}^{\mathrm{+}}\text{μ}{}^{\mathrm{?}}\text{)+}$ anything is calculated in the framework of the Drell-Yan model. We get very general expressions for the front-back asymmetry and the differential cross section in terms of the weak coupling constants and the parton distributions. Results for W^± production and proton-proton collisions are also given. Numerical estimates are made using various parton distributions and the Weinberg-Salam model for definiteness. We comment on the predictions of gauge theories that accommodate the absence of parity violating effects in atomic physics. We also give a new estimate of the inclusive cross sections $\text{p}\text{p}$ or pp → Z(→ μ⁺μ^?) or W^±(→ μ^±ν_μ) + anything. The effects of asymptotic freedom in the frontback asymmetries and the total cross sectons are investigated. We reanalyze results for the purely leptonic reaction e⁺e^? → γ, Z → μ⁺μ^?.