Scattering of very light scalar particles,off leptons

Within the scope of a new diquark model for deep inelastic structure functions presented by us recently we use the existing data onF ₁ ^ep (x,Q²) to learn about the admixture of spin-1 diquarks in nucleons. It turns out that they are so rare, heavy and extended compared to spin-0 diquarks that they are presumably accidental and not dynamical. Their number and form factors can be understood qualitatively within this picture. Still, the spin-1 diquarks give interesting structures in data and, together with quarks and spin-0 diquarks, carry enough momentum to account for the full nucleon energy. A gluon component is hence not needed in the nucleon!     

Diquark breakup in high-energy neutrino interactions

We examine the experimental tests and theoretical predictions for diquark breakup in high-energy neutrino interactions. Most tests of diquark breakup are found to be inconclusive and the only compelling evidence comes from lambda production in νp interactions.     

Present status of the opera experiment for the direct observation of neutrino oscillations in the νμ → ν τ channel

The OPERA experiment (Oscillation Project with an Emulsion-Tracking Apparatus) for the direct observation of neutrino oscillations in the ν_μ → ν _τ channel has been underway at the underground laboratory in Gran Sasso since 2007. In the course of data collection, more than 3000 ν_μ interactions have been registered in emulsion detectors. Twenty charmed neutrino interaction candidates have been found. Multidimensional criteria have been developed in order to select ν _τ interactions against νμ interactions accompanied by charmed hadron production. The first results from automated PAVIKOM emulsion scanning have been obtained. We discuss the measurements of the muon charge ratio of μ⁺ to μ^?.     

Infrared spectrum of formaldehyde: Coriolis interactions in the combination bands ν2 + ν6 and ν2 + ν3

A high-resolution infrared spectrum of H₂CO was measured in the range from 2600 to 3300 cm^?1. Vibration-rotation lines assigned to the combination bands ν₂ + ν₃ (a-type) and ν₂ + ν₆ (b-type) were analyzed as asymmetric-rotor bands by taking account of the Coriolis interactions among the ν₂ + ν₃, ν₂ + ν₆, and ν₂ + ν₄ states, though none of the ν₂ + ν₄ band lines have yet been definitely identified. The main results in cm^?1 units (with 2.5 times standard errors in the last digits given in parentheses) are: ν₀ = 3238.45(1), A - B?= 8.252(3), B?= 1.2053(2), and B - C = 0.1719 (assumed) for ν₂ + ν₃; ν₀ = 3000.10(1), A - B?= 8.125(46), B?= 1.2075(5), and B - C = 0.1693(14) for ν₂ + ν₆; and ν₀ = 2904.6(48), A - B?= 8.225(54), B?= 1.2023(20), and B - C = 0.1522 (assumed) for ν₂ + ν₄; the effective Coriolis interaction terms are: ξ_26,24^a = 10.10(3)cm^?1 and ξ_23,26^c = 0.96(3)cm^?1 under the assumption that ξ_23,24^b = 1.2841cm^?1. A second combination band 2ν₂ + ν₆ measured with lower resolution gave ν₀ = 4734.81(6)cm^?1.     

Large-pT protons from constituent diquark scattering

Recent data from the CERN ISR on the fractional proton yield in pp collisions are explained within the Stockholm diquark model. Describing the proton as a u(ud)₀ system, the observed high magnitude and fall-off _pT, θ and $\text{s}$ of the proton yield are natural consequences of constituent diquark elastic scattering. The _pT and θ dependence favour a value of around 10 GeV²/c² for the size parameter in the diquark form factor, corresponding to a diquark rms radius of around 0.2 fm. This is consistent with earlier results of the model applied to deep inelastic lepton-nucleon scattering and e⁺e^? annihilation.     

Precision infrared spectroscopy in CF379Br by means of infrared-microwave double resonance

From the observation of double resonance effects on the microwave spectrum two coincidences between 9.4 μm CO₂ laser lines and infrared transitions of the ν₆ → (ν₆ + ν₁) band of CF₃⁷⁹Br have been determined: R(30) laser line coincident with ^qR₂(7), F = 17/2→17/2 transition, R(28) laser line coincident with all four ΔF = 0 hyperfine components of the ^qQ₈(13) transition. In both cases other infrared transitions lay within the tuning range of the laser. The frequencies of these two laser lines allowed calculations of the band center frequency ν₀ = 1083.530 ± 0.001cm^?1 and α_A = 11.93 ± 0.3MHz, for the ν₆ → (ν₆ + ν₁) band.α_B constants were determined for the vibrational states v₆, (v₆ + v₁), v₁, and v₃.     

Composite nucleon approach to the deuteron problem

A composite model is suggested for the nucleons by assuming a longrange strong gluon force between a diquark boson B and a quark A. In the proton, A is trapped inside B in an oscillator potential and, in the neutron, A is on the surface of B in a hydrogenlike state. Nucleon form factors are obtained in agreement with experiments. The model contains a mechanism for a large effective mass of the quark A. When B is identified with π and A with μ, one can fix the gluon charge value and obtain the magnetic moments of the proton and neutron. The (πμ) atomic model for the nucleon can be used to construct the deuteron on a hydrogen molecule model. It leads to values for the binding energy, electric quadrupole moment, and form factors of the deuteron that are in agreement with experiments.     

The infrared spectrum of C3O2: The interaction between ν7 and the ν2 and ν4 vibrations

The 3ν¹₇, 3ν³₇, and 4ν⁰₇ hot bands of the ν₄ fundamental of C₃O₂ in the 1580 cm^?1 region were analyzed from tunable diode laser spectra and the ground state to ν₄ + 2ν⁰₇ band at 1644 cm^?1 from Fourier transform spectra (FTS). The molecular constants for all of the v₄ 1 ← 0 bands as well as the intensity of the ν₀ + 2ν⁰₇ sum band relative to the ν₄ fundamental were in agreement with the predictions of the model of Weber and Ford. FTS spectra at 0.05 cm^?1 resolution were obtained of the sum and difference bands of ν₂ with ν₇ in the 750–900 cm^?1 region. Sharp Q branches occur for each ν₇ state in the sum bands, but only a number of R-branch bandheads and no recognizable Q branches in the difference bands. Assignments of the sum band Q branches through v₇ = 6 were made and molecular constants were determined for the ν₂ + ν¹₇ ← 0 transition at 819.7 cm^?1. The ν₇ potential function in the v₂ = 1 state was found to have a 1.2 cm^?1 barrier with a minimum at α = 4.9°, where 2α is the angular deviation from linearity. The Q-branch positions predicted from the calculated energy levels fit those observed within several cm^?1.     

High resolution infrared spectroscopy of [1.1.1]propellane: The region of the ν9 band

The region of the infrared-active band of the ν₉ CH₂ bending mode [1.1.1]propellane has been recorded at a resolution (0.0025 cm⁻¹) sufficient to distinguish individual rovibrational lines. This region includes the partially overlapping bands ν₉ (e′) = 1459 cm⁻¹, 2ν₁₈ (l = 2, E′) = 1430 cm⁻¹, ν₆ + ν₁₂ (E′) = 1489 cm⁻¹, and ν₄ + ν₁₅ (A₂″) = 1518 cm⁻¹. In addition, the difference band ν₄ − ν₁₅ (A₂″) was observed in the far infrared near 295 cm⁻¹ and analyzed to give good constants for the upper ν₄ levels. The close proximities of the four bands in the ν₉ region suggest that Coriolis and Fermi resonance couplings could be significant and theoretical band parameters obtained from Gaussian ab initio calculations were helpful in guiding the band analyses. The analyses of all four bands were accomplished, based on our earlier report of ground state constants determined from combination differences involving more than 4000 pairs of transitions from five fundamental and four combination bands. This paper presents the analyses and the determination of the upper state constants of all four bands in the region of the ν₉ band. Complications were most evident in the 2ν₁₈ (l = 2, E′) band, which showed significant perturbations due to mixing with the nearby 2ν₁₈ (l = 0, A₁′) and ν₄ + ν₁₂ (E′) levels which are either infrared inactive as transitions from the ground state, or, in the latter case, too weak to observe. These complications are discussed and a comparison of all molecular constants with those available from the ab initio calculations at the anharmonic level is presented.     

High resolution infrared spectrum of the ν4 band of DCCF

The bending vibration-rotation band ν₄ of DCCF was studied. The measurements were carried out with a Fourier spectrometer at a resolution of about 0.03 cm^?1. The constants B₀=0.29141(1)cm^?1, α₄=?5.02(2)×10^?4cm^?1, q₄=4.52(3)×10^?4cm^?1, and D₀=9.2(4)×10^?8cm^?1 were derived. The rotational analysis of the “hot” bands 2ν₄(Δ) ← ν₄(II) and 2ν₄(Σ⁺) ← ν₄(II) was performed. In addition, the “hot” bands ν₄ + ν₅ ← ν₅ were assigned. A set of vibrational constants involved was derived.     

Vibrational-rotational Einstein coefficients for HF/DF and HCl/DCl

The RKR potential functions have been combined with the best experimentally based dipole functions to calculate the Einstein coefficients for HF/DF and HCl/DCl. Calculations were done for the Δν = 1,2,3 transitions for a wide range of ν′ (?15 for HF/DF and ?8 for HCl/ DCl) and J′ (?25). Experimental tests involving comparison of P- and R-branch line intensities for high-J′ transitions of the HF (ν₁ → ν₀, ν₂ → ν₁ and ν₃ → ν₂ bands) and the Δν = 2 and Δν = 1 transitions for HF/DF and HCl are done to examine the reliability of the Einstein coefficients for the rotational and vibrational levels, respectively. Good agreement is obtained for HF/DF even for the high-J′ R-branch intensities which vary markedly with J′. But the data suggest improvement is needed in the dipole functions for HCl (and DCl).     

Assignment, fit, and theoretical discussion of the ν10 band of acetaldehyde near 509 cm

The lowest small-amplitude vibration in acetaldehyde (CH₃CHO) is the in-plane aldehyde scissors mode ν₁₀ at 509 cm⁻¹. This mode lies about 175 cm⁻¹ above the top of the barrier to internal rotation of the methyl group and is relatively well separated from other small-amplitude vibrational states (the next fundamental occurring more than 250 cm⁻¹ higher). It thus provides an excellent example of an isolated small-amplitude fundamental (bright state) embedded in a bath of dark states. Since the bath states at these energies are not too dense, and since they arise purely from states of the large-amplitude torsional vibration of the methyl rotor, a detailed spectroscopic analysis of interactions between the bright state and the bath states should be possible. This paper represents the first step toward that goal. We have assigned several thousand transitions in the ν₁₀ band (J ? 28, K ? 12), and have carried out a simultaneous fit of 2400 of these transitions (J ? 15, K ? 9) with over 8100 transitions to the torsional bath state levels. Three vibration-torsion interactions, which give rise to rather global level shifts of the order of 1 cm⁻¹ in the ν₁₀ levels, have been identified and quantitatively fit. A number of vibration-torsion-rotation interactions, which give rise to localized (avoided-crossing) shifts in ν₁₀ have also been determined. The present analysis indicates the need for reliable spectroscopic information on more of the torsional bath states in the immediate vicinity of the ν₁₀ levels. Possible ways of obtaining such information in future studies are considered.     

A QCD Sum Rule Approach with an Explicit Di-quark Field

We introduce a phenomenological QCD sum rule with an explicit diquark field. We investigate certain configurations of hadrons are expected to have a good diquark structure. The parameters of the model are a diquark mass ${(m_\phi)}$ and condensate ${(\langle \phi^2\rangle)}$ . Assuming that Λ baryons can be represented by a diquark and a spectator quark configuration, we find the sum rule works well for Λ, Λ _c , and Λ _b . We also find a duality relation between the mass and the condensate for which the parameter sets give good Borel curves. To maintain good Borel curve, a smaller diquark condensate is needed for an increased diquark mass. Using these parameter sets, we test the diquark structure in some hadrons which contain both good and bad diquark configurations.     

Precise measurement of the frequency separation between the F(2)2 and the E lines in methane

The methane E line at 2947.811 cm^-1 has been observed by the saturated absorption technique using a Zeeman shifted 3.39 μm He-Ne laser. The frequency separation between this line and the F(²)₂ line in methane, commonly used as an infrared frequency reference, is measured to be ν(F²₂) - ν(E) = 3032560 ± 5 kHz. It has been checked that the E line is free from power and Stark frequency shifts within our 5 kHz measurement precision.     

Bound diquarks and their Bose–Einstein condensation in strongly coupled quark matter

We explore the formation of diquark bound states and their Bose–Einstein condensation (BEC) in the phase diagram of three-flavor quark matter at nonzero temperature, T, and quark chemical potential, μ  . Using a quark model with a four-fermion interaction, we identify diquark excitations as poles of the microscopically computed diquark propagator. The quark masses are obtained by solving a dynamical equation for the chiral condensate and are found to determine the stability of the diquark excitations. The stability of diquark excitations is investigated in the T–μ$T\text{–}\mu$ plane for different values of the diquark coupling strength. We find that diquark bound states appear at small quark chemical potentials and at intermediate coupling strengths. Bose–Einstein condensation of non-strange diquark states occurs when the attractive interaction between quarks is sufficiently strong.     

New High-Resolution Analysis of the ν7 and ν9 Fundamental Bands of trans-Formic Acid by Fourier Transform Infrared and Millimeter-Wave Spectroscopy

The high-resolution (0.002 cm⁻¹) spectrum of the ν₇ (OCO scissor mode) and ν₉ (COH torsion mode) fundamental bands of trans-formic acid (HCOOH) at 15.8 μm was recorded by Fourier transform infrared spectroscopy. In addition, millimeter-wave transitions within the 7¹ and 9¹ vibrational states were measured in the spectral range 340-600 GHz. Using these new experimental data, an extensive analysis of the ν₇ and ν₉ bands was performed. The model we have used accounts for the strong A- and B-type Coriolis interactions which couple the 7¹ and 9¹ vibrational states and which were already pointed out in the literature [J. C. Deroche, J. Kauppinen and E. Kyrö, J. Mol. Spectrosc.78, 379-394 (1979); E. Willemot, J. Mol. Spectrosc.120, 246-275 (1986)]. The observed levels are fit to within the experimental accuracy leading to the determination of a precise set of band centers of ν₇ and ν₉ at 686.1656 cm⁻¹ and 640.7251 cm⁻¹, respectively, and rotational and Coriolis constants.     

A Kerr effect study of microwave behaviour of partially magnetised ferrites

Magneto-microwave Kerr effect has been experimentally studied on three ferrite samples in the Polder-Smit loss region. Experimental data have been compared with the theoretical values which were calculated on the basis that the real part of the permeability tensor element μ′ is given by Green and Sandy's expressions (IEEE Trans. Microwave Theory Tech. MTT-22, 641 (1974)). This has a term given by Schlomann for μ′₀, the permeability for the demagnetised state. No agreement is found between theoretical and experimental values hence the above expression for ν′₀ has been substituted by another one given by Sandy (Raytheon Tech. Memor. T-815 (1969)) which involves the average demagnetisation factor N. It is found that there is a good agreement between the theory and the experiment provided N is assumed to depend linearly on the magnetisation of the sample.     

Analysis of ν2, ν4 Infrared Hot Bands of SO3: Resolution of the Puzzle of the ν1 CARS Spectrum

Further analysis of the high-resolution (0.0015 cm⁻¹) infrared spectrum of ³²S¹⁶O₃ has led to the assignment of more than 3100 hot band transitions from the ν₂ and ν₄ levels to the states 2ν₂ (l=0), ν₂+ν₄ (l=±1), and 2ν₄ (l=0,±2). These levels are strongly coupled via Fermi resonance and indirect Coriolis interactions to the ν₁ levels, which are IR-inaccessible from the ground state. The unraveling of these interactions has allowed the solution of the unusual and complicated structure of the ν₁ CARS spectrum. This has been accomplished by locating over 400 hot-band transitions to levels that contain at least 10% ν₁ character. The complex CARS spectrum results from a large number of avoided energy-level crossings between these states. Accurate rovibrational constants are deduced for all the mixed states for the first time, leading to deperturbed values of 1064.924(11), 0.000 840 93(64), and 0.000 418 19(58) cm⁻¹ for ν₁, α₁^B, and α₁^C, respectively. The uncertainties in the last digits are shown in parentheses and represent two standard deviations. In addition, new values for some of the anharmonicity constants have been obtained. Highly accurate values for the equilibrium rotational constants B_e and C_e are deduced, yielding independent, nearly identical values for the SO r_e bond length of 141.734 03(13) and 141.732 54(18) pm, respectively.     

Absolute Line Intensities in Acetylene: The 1.5-μm Region

We measured 305 absolute line intensities in the ν₁+ν₃(Σ⁺_u)-0(Σ⁺_g) band of ¹²C₂H₂ and ¹³C¹²CH₂ and the ν₁+ν₂+(ν¹₄+ν⁻¹₅)⁰(Σ⁺_u)-0(Σ⁺_g), ν₁+ν₃+ν¹₄(Π_g)-ν¹₄(Π_g), and ν₁+ν₃+ν₅¹(Π_u)-ν₅¹(Π_u) bands of the main isotopomer, all observed near 1.5 μm. The absolute intensity of these bands are respectively 6.4882 (34), 0.12337 (10), 0.083746 (71), 0.58771 (28), and 0.32126 (11) cm⁻² atm⁻¹ at 296 K. In addition, we also determined Herman-Wallis factors for the first time in this spectral region.     

Absorption intensities for vibration-rotation bands and the dipole-moment expansion of HBr

Line intensities in the four 0–2, 0–3, 0–4, 0–5 vibration-rotation bands of HBr were measured. The electric dipole matrix elements 〈0|M|ν'〉 for vibrational transitions with ν'?5 have been calculated by using a Dunham potential and the analytical solution of the Schrödinger equation described by R.H. Tipping. A dipole-moment expansion accurate to M₅ was determined by fitting these matrix elements to the available experimental data on line intensities. The experimental results were also used to calculate the Einstein coefficients of the R₀ lines for the bands ν' → ν′' with ? ν' ? 5.