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V. V. Anisovich

Publications and source records attributed to V. V. Anisovich.

At least 37 records · Page 2Linked to original sources
arXiv2011

Sigma-Meson and Confinement Singularity

We describe the meson-meson data for the ($IJ^{PC}=00^{++}$) wave at $280\leq\sqrt s\leq 1900$ MeV in two approaches: (i) the K-matrix approach and (ii) the dispersion relation D-matrix method. With a good description of low energy data (at $280\leq\sqrt s\leq 900$ MeV) as well as the data of two-meson transition amplitudes and antiproton-proton annihilation into three pseudoscalar meson states (at $450\leq\sqrt s\leq 1950$ MeV) we have found the positions of the resonance poles: (i) for the $σ$ meson pole: $M_σ= (390\pm 35)-i(235\pm 50)$ MeV; (ii) two poles for the $f_0(980)$, on the second sheet (under the $ππ$ cut): $M_{I} = (1011\pm 5)-i(35\pm 5)$ MeV, and on the third sheet (under the $ππ$ and $K\bar K$ cuts), $M_{II} = (1035\pm 50)-i(460\pm 50)$ MeV; for the $f_0(1370)$ meson, $M= (1285\pm 30)-i(160\pm 20)$ MeV; for the $f_0(1500)$ meson, $M = (1488\pm 4)-i(53\pm 5)$ MeV; for the $f_0(1790)$ meson, $M = (1775\pm 25)-i(140\pm 15)$ MeV and for the broad state $f_0(1200-1600)$ $M=(1540\pm 120)-i(550\pm 70)$ MeV. Our estimation of the scalar-isoscalar scattering length obtained under different parameterizations and assumptions about the quality of low energy $ππ$ scattering data is $a^0_0=(0.215\pm 0.040)μ^{-1}_π$. We also discuss the idea according to which the $σ$-meson could be a remnant of the confinement singularity, $1/s^2$, in a white channel.

hep-ph↗
arXiv2010

Colour effective particles and confinement

Here I present a brief review of papers where the idea is pushed forward that colour confinement is realized by singular interaction at large distances between colour effective particles (constituent quarks, diquarks, massive effective gluons).

hep-ph↗
arXiv2010

Quark-diquark Systematics of Baryons: Spectral Integral Equations for Systems Composed by Light Quarks

For baryons composed by the light quarks ($q=u,d$) we write spectral integral equation using the notion of two diquarks: (i) axial--vector state, $D^{1}_{1}$, with the spin $S_D=1$ and isospin $I_D=1$ and (ii) scalar one, $D^{0}_{0}$, with the spin $S_D=0$ and isospin $I_D=0$. We present spectral integral equations for the $qD^{0}_{0}$ and $qD^{1}_{1}$ states taking into account quark--diquark confinement interaction.

hep-ph↗
arXiv2010

Quark--Diquark Systematics of Baryons and the SU(6)SYMMETRY for Light States

We continue our attempts to systematize baryons, which are composed of light quarks ($q=u,d$), as quark--diquark systems. The notion of two diquarks is used: (i) $D^{1}_{1}$, with the spin $S_D=1$ and isospin $I_D=1$ and (ii) $D^{0}_{0}$, with $S_D=0$ and $I_D=0$. Here we try to resolve the problem of the low-lying $Δ(\frac 52^-)$ states: in the last experiments the lightest state is observed at $\ga 2200$ MeV, not at $1900 - 2000$ MeV as it has been stated 20 years ago. We are looking for different systematization variants with the forbidden low-lying $Δ(\frac 52^-)$ states in the mass region $\la 2000$ MeV. We see that the inclusion of the SU(6) constraints on $qD^{1}_{1}$ states with angular momentum L=1 results in a shift of the lightest $Δ(\frac 52^-)$ isobar to $\sim 2300$ MeV. The scheme with the SU(6) constraints for low-lying $qD^{1}_{1}$ and $qD^{0}_{0}$ states (with $L=0,1$) is presented in detail here.

hep-ph↗
arXiv2010

Searching for the quark--diquark systematics of baryons composed by light quarks $q=u,d$

Supposing quark--diquark structure of baryons, we look for systematics of baryons composed of light quarks ($q=u,d$). We systematize baryons using the notion of two diquarks: (i) axial--vector state, $D^{1}_{1}$, with the spin $S_D=1$ and isospin $I_D=1$ and (ii) scalar one, $D^{0}_{0}$, with the spin $S_D=0$ and isospin $I_D=0$. We consider several schemes for the composed baryons: (1) with different diquark masses, $M_{D^0_0} \ne M_{D^1_1}$, (2) with $M_{D^0_0} = M_{D^1_1}$ and overlapping $qD^0_0$ and $qD^1_1$ states (resonances), (3) with/without SU(6) constraints for low-lying states (with quark--diquark orbital momenta L=0). In the high-mass region the model predicts several baryon resonances at $M\sim 2.0-2.9$ GeV. Moreover, the model gives us the double pole structure (i.e. two poles with the same Re$M$ but different Im$M$) in many amplitudes at masses $M\ga 2.0$ GeV. We see also that for description of low-lying baryons (with L=0), the SU(6) constraint is needed.

hep-ph↗
arXiv2009

The analysis of reactions $πN\to two mesons + N$ within reggeon exchanges. 1. Fit and results

The novel point of this analysis is a direct use of reggeon exchange technique for the description of the reactions $πN\to two mesons + N$ at large energies of the initial pion. This approach allows us to describe simultaneously distributions over $M$ (invariant mass of two mesons) and $t$ (momentum transfer squared to nucleons). Making use of this technique, the following resonances (as well as corresponding bare states), produced in the $πN\to π^0π^0 N$ reaction are studied: $f_0(980)$, $f_0(1300)$, $f_0(1200-1600)$, $f_0(1500)$, $f_0(1750)$, $f_2(1270)$, $f_2(1525)$, $f_2(1565)$, $f_2(2020)$, $f_4(2025)$. Adding data for the reactions $p\bar p({\rm at rest, from liquid H_2})\to π^0π^0π^0$, $π^0π^0η$, $π^0ηη$ and $p\bar p({\rm at rest, from gaseous H_2})\to π^0π^0π^0$, $π^0π^0η$, $π^0ηη$, we have performed simultaneous $K$-matrix fits of two-meson spectra in all these reactions. The results of combined fits to the above-listed isoscalar $f_J$-states and to isovector ones, $a_0(980)$, $a_0(1475)$, $a_2(1320)$, are presented.

hep-ph↗
arXiv2009

Two-pion decays of mesons and confinement singularities

We consider the two-pion decay of the $ρ$-meson, the $^3S_1q\bar q$-state of the constituent quarks -- the decay being determined by the transition $q\bar q\to ππ$ contains information about confinement interactions. One can specify in this decay two types of transitions: ({\bf i}) the bremsstrahlung radiation of a pion $q\to q+π$ (or $\bar q\to\bar q+π$) with the subsequent fusion $q\bar q\to π$, and ({\bf ii}) the direct transition $q\bar q\to ππ$. We demonstrate how in the amplitudes of the corresponding transitions the quark singularities have to disappear, {\it i.e.} what is the way the quark confinement at relatively short distances can be realized. We calculate and estimate the contributions of processes with bremsstrahlung radiation of the pion and of the direct transition $q\bar q\to ππ$. The estimates demonstrate that the processes involving the direct transition $q\bar q\to ππ$ are necessary, but they cannot be determined unambiguously by the decay $ρ(775)\to ππ$. We conclude that for the determination of the $q\bar q\to ππ$ transition more complete data on the resonance decays into the $ππ$ channels are required than those available at the moment.

hep-ph↗
arXiv2009

The rho -> gamma pi and omega -> gamma pi decays in quark-model approach and estimation of coupling for pion emission by quark

In the framework of the relativistic and gauge invariant spectral integral technique, we calculate radiative decays rho(770)-> gamma pi(140) and omega(780)-> gamma pi(140) supposing all mesons (pi, rho and omega) to be quark-antiquark states. The q anti-q wave functions found for mesons and photon lead to a reasonably good description of data ($Γ^{(exp)}_{ρ^{\pm} \toγπ^{\pm}}=68\pm 30$ keV, $Γ^{(exp)}_{ρ^{0}\toγπ^0}=77\pm 28$ keV, $Γ^{(exp)}_{ω\toγπ^0}=776\pm 45$ keV) that makes it possible to estimate the coupling for the bremsstrahlung emission of pion by quarks $g_π\equiv g_π(u\to d π)$. We have found two values for the pion bremsstrahlung coupling: $|g_π|=16.7 \pm 0.3 ^{+0.1}_{-2.3}$ (Solution I) and $|g_π|=3.0 \pm 0.3 ^{+0.1}_{-2.1}$ (Solution II). Within SU(6)-symmetry for nucleons, Solution I gives us for pi NN coupling the value $16.4 \le g_{πNN}^2/(4π) \le 23.2$ that is in qualitative agreement with the pi N scattering data, $g_{πNN}^2/(4π)\simeq 14$. For excited states, we have estimated the partial widths in Solution I as follows: $Γ(ρ_{2S}^\pm\to γπ)\simeq 10 - 130$ keV, $Γ(ρ_{2S}^0\to γπ)\simeq 10 -130$ keV, $Γ(ω_{2S}\to γπ)\simeq 60 - 1080$ keV. The large uncertainties emphasise the necessity to carry out measurements of the meson radiative processes in the region of large masses.

hep-ph↗
arXiv2007

Baryon-baryon and baryon-antibaryon interaction amplitudes in the spin--momentum operator expansion method

Partial wave scattering amplitudes in baryon-baryon and baryon-antibaryon collisions and amplitudes for the production and decay of baryon resonances are constructed in the framework of the spin-momentum operator expansion method. The approach is relativistically invariant and it allows us to perform combined analyses of different reactions imposing analyticity and unitarity directly. The role of final state interactions (triangle and box diagrams) is discussed.

hep-ph↗
arXiv2006

Once again about the reaction phi(1020)-> gamma-pi-pi

Gauge invariance constraints and analytical properties of the amplitudes e+ e- -> gamma-pi-pi and phi(1020) -> gamma-pi-pi are discussed in line with the criticism of N.N. Achasov in hep-ph/0606003. I show that the formulae of our paper (Yad. Fiz. {\bf 68} 1614 (2005) [PAN {\bf 68} 1554 (2005)], hep-ph/0403123) have nothing common with those N.N. Achasov claims to be ours - his criticism is therefore misplaced.

hep-ph↗
arXiv2005

Quark--antiquark states and their radiative transitions in terms of the spectral integral equation. {\Huge I.} Bottomonia

In the framework of the spectral integral equation, we consider the $b\bar b$ states and their radiative transitions. We reconstruct the $b\bar b$ interaction on the basis of data for the levels of the bottomonium states with $J^{PC}=0^{-+}$, $1^{--}$, $0^{++}$, $1^{++}$, $2^{++}$ as well as the data for the radiative transitions $Υ(3S) \toγχ_{bJ}(2P) $ and $Υ(2S) \toγχ_{bJ}(1P) $ with $J=0,1,2$. We calculate bottomonium levels with the radial quantum numbers $n\le 6$, their wave functions and corresponding radiative transitions. The ratios $Br[χ_{bJ}(2P)\toγΥ(2S)]/Br[χ_{bJ}(2P)\toγΥ(1S)]$ for $J=0,1,2$ are found in the agreement with data. We determine the $b\bar b$ component of the photon wave function using the data for the $e^+e^-$ annihilation, $e^+e^- \toΥ(9460)$, $Υ(10023)$, $Υ(10036)$, $Υ(10580)$, $ Υ(10865)$, $Υ(11019)$, and predict partial widths of the two-photon decays $η_{b0}\to\ggam$, $χ_{b0}\to\ggam$, $χ_{b2}\to\ggam$ for the radial excitation states below $B\bar B$ threshold ($n\le 3$).

hep-ph↗
arXiv2005

Quark--antiquark states and their radiative transitions in terms of the spectral integral equation. {\Huge II.} Charmonia

In the precedent paper of the authors (hep-ph/0510410), the $b\bar b$ states were treated in the framework of the spectral integral equation, together with simultaneous calculations of radiative decays of the considered bottomonia. In the present paper, such a study is carried out for the charmonium $(c\bar c)$ states. We reconstruct the interaction in the $c\bar c$-sector on the basis of data for the charmonium levels with $J^{PC}=0^{-+}$, $1^{--}$, $0^{++}$, $1^{++}$, $2^{++}$, $1^{+-}$ and radiative transitions $ψ(2S)\toγχ_{c0}(1P)$, $γχ_{c1}(1P)$, $γχ_{c2}(1P)$, $γη_{c}(1S)$ and $χ_{c0}(1P)$, $χ_{c1}(1P)$, $χ_{c2}(1P)\toγJ/ψ$. The $c\bar c$ levels and their wave functions are calculated for the radial excitations with $n\le 6$. Also, we determine the $c\bar c$ component of the photon wave function using the $e^+e^-$ annihilation data: $e^+e^- \to J/ψ(3097)$, $ψ(3686)$, $ψ(3770)$, $ψ(4040)$, $ ψ(4160)$, $ψ(4415)$ and perform the calculations of the partial widths of the two-photon decays for the $n=1$ states: $η_{c0}(1S)$, $χ_{c0}(1P)$, $χ_{c2}(1P)\toγγ$, and $n=2$ states: $η_{c0}(2S)\toγγ$, $χ_{c0}(2P)$, $χ_{c2}(2P)\to γγ$. We discuss the status of the recently observed $c\bar c$ states X(3872) and Y(3941): according to our results, the X(3872) can be either $χ_{c1}(2P)$ or $η_{c2}(1D)$, while Y(3941) is $χ_{c2}(2P)$.

hep-ph↗
arXiv2005

Quark--antiquark states and their radiative transitions in terms of the spectral integral equation. {\Huge III.} Light mesons

We continue the investigation of mesons in terms of the spectral integral equation initiated before [hep-ph/0510410, hep-ph/0511005] for the $b\bar b$ and $c\bar c$ systems: in this paper we consider the light-quark ($u, d,s$) mesons with masses $M\le 3$ GeV. The calculations have been performed for the mesons lying on linear trajectories in the $(n,M^2)$-planes, where $n$ is the radial quantum number. Our consideration relates to the $q\bar q$ states with one component in the flavor space, with the quark and antiquark masses equal to each other, such as $π(0^{-+})$, $ρ(1^{--})$, $ω(1^{--})$, $ϕ(1^{--})$, $a_0(0^{++})$, $a_1(1^{++})$, $a_2(2^{++})$, $b_1(1^{+-})$, $f_2(2^{++})$, $π_2(2^{-+})$, $ρ_3(3^{--})$, $ω_3(3^{--})$, $ϕ_3(3^{--})$, $π_4(4^{-+})$ at $n\le 6$. We obtained the wave functions and mass values of mesons lying on these trajectories. The corresponding trajectories are linear, in agreement with data. We have calculated the two-photon decays $π\to γγ$, $a_0(980)\to γγ$, $a_2(1320)\to γγ$, $f_2(1285)\to γγ$, $f_2(1525)\to γγ$ and radiative transitions $ρ\toγπ$, $ω\toγπ$, that agree qualitatively with the experiment. On this basis, we extract the singular part of the interaction amplitude, which corresponds to the so-called "confinement interaction". The description of the data requires the presence of the strong $t$-channel singularities for both scalar and vector exchanges.

hep-ph↗
arXiv2005

Scalar mesons and low-mass sigma: Does the $σ$ reveal the confinement singularity?

I present a short review of the current understanding of the scalar meson sector, with special attention to the problem of the low-mass $σ$. The dispersion relation $N/D$-method used for the restoration of the low-energy $ππ$ $(IJ^{PC}=00^{++})$-wave amplitude is discussed. The low-energy $ππ$ amplitude was determined from the data in the energy region 280--500 MeV and it was sewn with the previously found $K$-matrix solution for the region 450--1950 MeV. The $N/D$-amplitude has a pole on the second sheet of the complex-$s$ plane, near the $ππ$ threshold at $\sqrt s \simeq 430-i325$ MeV, that corresponds to the low-mass $σ$-meson. I discuss the hypothesis that this pole may be related to the confinement forces, thus being the eyewitness of confinement.

hep-ph↗
arXiv2005

Radiative decays of quarkonium states, momentum operator expansion and nilpotent operators

We present the method of calculation of radiative decays of composite quark-antiquark systems with different J^{PC}: (Q\bar Q)_{in} -> gamma (Q\bar Q)_{out}. The method is relativistic invariant, it is based on the double dispersion relation integrals over the masses of composite mesons, it can be used for the high spin particles and provides us with the gauge invariant transition amplitudes. We apply this method to the case when the photon is emitted by a constituent in the intermediate state (additive quark model). We perform the momentum operator expansion of the spin amplitudes for the decay processes. The problem of nilpotent spin operators is discussed.

hep-ph↗