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V. V. Anisovich

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

At least 55 records · Page 3Linked to original sources
arXiv2005

Sector of the $2^{++}$ mesons: observation of the tensor glueball

Data of the Crystal Barrel and L3 collaborations clarified essentially the situation in the $2^{++}$ sector in the mass region up to 2400 MeV, demonstrating the linearity of $(n,M^2)$ trajectories, where $n$ is the radial quantum number of a quark-antiquark state with mass $M$. We discuss these data and show that there exists a superfluous state for the $(n,M^2)$ trajectories: a broad resonance $f_2(2000)$. We pay special attention to the reactions $p\bar p\toππ,ηη,ηη'$ in the mass region 1990--2400 MeV where, together with $f_2(2000)$, four relatively narrow resonances are seen: $f_2(1920)$, $f_2(2020)$, $f_2(2240)$, $f_2(2300)$. We analyse the branching ratios of all these resonances and show that only the decay couplings of the broad state $f_2(2000)\toπ^0π^0,ηη, ηη'$ satisfy relations inherent in the glueball decay.

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arXiv2005

Observation of Observation of tensor glueball in the reactions p anti-p -> pi-pi, eta-eta, eta-eta'

Partial wave analysis of the reactions p anti-p -> pi-pi, eta-eta, eta-eta' in the region of invariant masses 1900-2400 MeV indicates to the existence of four relatively narrow tensor-isoscalar resonances f_2(1920), f_2(2020), f_2(2240), f_2(2300) and the broad state f_2(2000). The determined decay couplings of the broad resonance f_2(2000)-> pi0-pi0, eta-eta, eta-eta' satisfy the relations appropriate to those of tensor glueball, while the couplings of other tensor states do not, thus verifying the glueball nature of f_2(2000).

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arXiv2005

Determination of the quarkonium--gluonium content of the isoscalar tensor resonances $f_2(1920)$, $f_2(2020)$, $f_2(2240)$, $f_2(2300)$ and of the broad state $f_2(2000)$ based on decay couplings to $π^0π^0,ηη,ηη'$

In the reactions $p\bar p\toπ^0π^0,ηη,ηη'$ there are four relatively narrow resonances $f_2(1920)$, $f_2(2020)$, $f_2(2240)$, $f_2(2300)$, and a broad one $f_2(2000)$ in the mass region 1990--2400 MeV. In the framework of quark combinatorics we carry out an analysis of the decay constants for all five resonances. It is shown that the relations for the decay constants corresponding to the broad resonance $f_2(2000)\toπ^0π^0,ηη, ηη'$ are the same as those corresponding to a glueball. An additional argument in favour of the glueball--nature of $f_2(2000)$ is the fact that $f_2(1920)$, $f_2(2020)$, $f_2(2240)$, $f_2(2300)$ fit well the $q\bar q$ trajectories in the $(n,M^2)$-plane (where $n$ is the radial quantum number), while the broad $f_2(2000)$ resonance turns out to be an unnecessary extra state for these trajectories.

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arXiv2004

Decay $ϕ(1020)\to γf_0(980)$: analysis in the non-relativistic quark model approach

We demonstrate the possibility of a good description of the processes $ϕ(1020)\to γππ$ and $ϕ(1020)\to γf_0(980)$ within the framework of non-relativistic quark model assuming $f_0(980)$ to be dominantly quark--antiquark system. Different mechanisms of the radiative decay, that is, the emission of photon by the constituent quark (additive quark model) and charge-exchange current, are considered. We also discuss the status of the threshold theorem applied to the studied reactions, namely, the behaviour of the decay amplitude at $M_{ππ} \to m_ϕ$ and $m_{f_0}\to m_ϕ$. In conclusion the arguments favouring the $q\bar q$ origin of $f_0(980)$ are listed.

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arXiv2004

Systematization of tensor mesons and the determination of the $2^{++}$ glueball

It is shown that new data on the $(J^{PC}=2^{++})$-resonances in the mass range $M\sim1700-2400 $MeV support the linearity of the $(n,M^2)$-trajectories, where $n$ is the radial quantum number of quark--antiquark state. In this way all vacancies for the isoscalar tensor $q\bar q$-mesons in the range up to 2450 MeV are filled in. This allows one to fix the broad $f_2$-state with $M=2000\pm30 $MeV and $Γ=530\pm40 $MeV as the lowest tensor glueball. PACS numbers: 14.40.-n, 12.38.-t, 12.39.-Mk

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arXiv2004

Charmed quark component of the photon wave function

We determine the c-anti-c component of the photon wave function on the basis of (i) the data on the transitions e+ e- -> J/psi(3096), psi(3686), psi(4040), psi(4415), (ii) partial widths of the two-photon decays eta_{c0}(2979), chi_{c0}(3415), chi_{c2}(3556) -> gamma-gamma, and (iii) wave functions of the charmonium states obtained by solving the Bethe-Salpeter equation for the c-anti-c system. Using the obtained c-anti-c component of the photon wave function we calculate the gamma-gamma decay partial widths for radial excitation 2S state, eta_{c0}(3594) -> gamma-gamma, and 2P states chi_{c0}(3849), chi_{c2}(3950) -> gamma-gamma.

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arXiv2004

Radiative decays of mesons in the quark model: relativistic and non-relativistic approaches

Different conclusions about quark nature of f0(980) based on the analysis of data on the reaction phi(1020) -> gamma f0(980) make it necessary to perform detailed comparison of formulae used by various groups for the calculation of partial widths of radiative decays. We carry out a comparative analysis of methods of calculation of radiative decays like phi -> gamma f0 and phi -> gamma eta performed by F.E.Close et al., Phys. Rev. D 65, 092003 (2002), and A.V.Anisovich et al., Eur. Phys. J. A 12, 103 (2001); Yad. Fiz. 65, 523 (2002).

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arXiv2004

Systematics of quark-antiquark states and scalar exotic mesons

The analysis of the experimental data of Crystal Barrel Collaboration on the p anti-p annihilation in flight with the production of mesons in the final state resulted in a discovery of a large number of mesons over the region 1900-2400 MeV, thus allowing us to systematize quark-antiquark states in the (n,M^2) and (J,M^2) planes, where n and J are radial quantum number and spin of the meson with the mass M. The data point to meson trajectories in these planes being approximately linear, with a universal slope. The sector of scalar mesons is discussed in more detail, where, on the basis of the recent K-matrix analysis, the nonet classification of quark-antiquark states was performed: in the region below 2000 MeV, two scalar nonets are fixed, that is, the basic one and the nonet of the first radial excitation. In the scalar sector, there are two states with the isospin I=0, which are extra ones with respect to the quark--antiquark classification, i.e. exotic states: the broad resonance f0(1200-1600) and the light sigma-meson. The ratios of coupling constants for hadronic decays to the states pi pi, K anti-K, eta eta, eta eta' point to the gluonium nature of the broad state f0(1200-1600).

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arXiv2003

Systematics of quark-antiquark states: where are the lightest glueballs?

The analysis of the experimental data of Crystal Barrel Collaboration on the p anti-p annihilation in flight with the production of mesons in the final state resulted in a discovery of a large number of mesons over the region 1900-2400 MeV, thus allowing us to systematize quark-antiquark states in the (n,M^2) and (J,M^2) planes, where n and J are radial quantum number and spin of the meson with the mass M. The data point to meson trajectories in these planes being approximately linear, with a universal slope. Basing on these data and results of the recent K-matrix analysis a nonet classification is performed. In the scalar-isoscalar sector, the broad resonance state f0(1200-1600) is superfluous for the q anti-q classification, i.e. it is an exotic state. The ratios of coupling constants for the transitions f0-> pi pi, K anti-K, eta eta, eta eta' point to the gluonium nature of the broad state f0(1200-1600). The problem of the location of the lightest pseudoscalar glueball is also discussed.

hep-ph↗
arXiv2003

Description of composite systems in the spectral integration technique: the gauge invariance and analyticity constraints for the radiative decay amplitudes

The constraints followed from gauge invariance and analyticity are considered for the amplitudes of radiative transitions of composite systems when composite systems are treated in terms of spectral integrals. We discuss gauge-invariant amplitudes for the transitions S -> gamma S and V -> gamma S with scalar S and vector V mesons being two-particle composite systems of scalar (or pseudoscalar) constituents, and we demonstrate the mechanism of cancellation of false kinematical singularities. Furthermore, we explain how to generalize the performed consideration for quark-antiquark systems, in particular, for the reaction phi(1020) -> gamma f0(980). Here we also consider in more detail the quark-model non-relativistic approach for this reaction.

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arXiv2003

D^+_s -> pi^+ pi^+ pi^- decay: the 1^3P_0 s anti-s component in scalar-isoscalar mesons

On the basis of data on the decay D^+_s -> pi^+ pi^+ pi^-, which goes dominantly via the transition D_s -> pi^+ s anti-s, we evaluate the 1^3P_0 s anti-s components in the scalar-isoscalar resonances f0(980), f0(1300), f0(1500) and broad state f0(1200-1600)$. The data point to a large s anti-s component in the f0(980): 40% < s anti-s < 70%. Nearly 30% of the 1^3P_0 s anti-s component flows to the mass region 1300-1500 MeV being shared by f0(1300), f0(1500) and broad state f0(1200-1600): the interference of these states results in a peak near 1400 MeV with the width around 200 MeV.

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arXiv2002

K-matrix analysis of the (IJ^{PC}=00^{++})-wave in the mass region below 1900 MeV

We present the results of the current analysis of the partial wave IJ^{PC}=00^{++} based on the available data for meson spectra (pi-pi, K\bar K, eta-eta, eta-eta', pi-pi-pi-pi). In the framework of the K-matrix approach, the analytical amplitude has been restored in the mass region 280 MeV< \sqrt s <1900 MeV. The following scalar-isoscalar states are seen: comparatively narrow resonances f_0(980), f_0(1300), f_0(1500), f_0(1750) and the broad state f_0(1200-1600). The positions of the amplitude poles (masses and total widths of the resonances) are determined as well as pole residues (partial widths to meson channels pi-pi, K\bar K, eta-eta, eta-eta', pi-pi-pi-pi). The fitted amplitude gives us the positions of the K-matrix poles (bare states) and the values of bare-state couplings to meson channels thus allowing the quark-antiquark nonet classification of bare states. On the basis of the obtained partial widths to the channels pi-pi, K\bar K, eta-eta, eta-eta', we estimate the quark/gluonium content of f_0(980), f_0(1300), f_0(1500), f_0(1750), f_0(1200-1600). For f_0(980), f_0(1300), f_0(1500) and f_0(1750), their partial widths testify the q\bar q origin of these mesons though being unable to provide precise evaluation of the possible admixture of the gluonium component in these resonances. The ratios of the decay coupling constants for the f_0(1200-1600) support the idea about gluonium nature of this broad state.

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arXiv2002

Two-photon partial widths of tensor mesons

We calculate partial widths of the gamma-gamma decay of the tensor q\bar q states a_2(1320), f_2(1270), f_2(1525), their radial excitations a_2(1660), f_2(1640), f_2(1800) as well as ^3F_2 q\bar q states. Calculations are performed in the framework of the same approach which was used before for the study of radiative decays f_0(980) -> gamma-gamma, a_0(980) -> gamma-gamma and phi(1020) -> gamma-f_0(980): the assumption made is that of q\bar q structure of f_0(980) and a_0(980) [A.V. Anisovich et al., Phys. Lett. B 456, 80 (1999); Eur. Phys. J. A 12, 103 (2001)]. The description of the decay partial widths for a_2(1320), f_2(1270), f_2(1525) and f_0(980), a_0(980) is reached with the approximately equal radial wave functions, thus giving a strong argument in favour of the fact that these scalar and tensor mesons are to be classified as members of the same P-wave q\bar q multiplet.

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arXiv2002

Process pi p -> pi pi N at high energies and moderate momenta transferred to the nucleon and the determination of parameters of the f_0(980) and f_0(1300)

We present the results of simultaneous analysis of the S-wave pi pi-spectra in the reactions pi^- p -> (pi^0 pi^0)_S n at p_{lab}=38 GeV/c (GAMS) and pi^- p -> (pi^+ pi^-)_S n at p_{lab}=18 GeV/c (E852 Collaboration) at moderate momenta transferred to the nucleon, |t| < 1.5 (GeV/c)^2. The t-distributions are described by the reggeized pi- and a_1-exchanges provided by the leading and daughter trajectories, while the M_{pi pi}-spectra are determined by a set of scalar-isoscalar resonances. With M_{pi pi}-distributions averaged over t-intervals, we have found several solutions given by different t-channel exchange mechanisms at |t| ~ (0.5-1.5) (GeV/c)^2, with resonance parameters close to each other. We conclude that despite a poor knowledge of the structure of the t-exchange, the characteristics of resonances such as masses and widths can be reliably determined using the processes under discussion. As to pole positions, we have found (1031 +/- 10) - i(35 +/- 6) MeV for f_0(980) and (1315 +/- 20) - i(150 +/- 30) MeV for f_0(1300).

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arXiv2001

Systematics of q anti-q states, scalar mesons and glueball

Basing on the latest results of the PNPI (Gatchina) and QM&W College (London) groups, I discuss systematics of the IJ^{PC} q anti-q states in terms of trajectories on the (n,M^2) plane, where n is the radial quantum number and M is its mass. In the scalar sector, which is the most interesting because of the presence of extra states with respect to the q anti-q systematics, I discuss: 1) the results of the K-matrix analysis of the spectra pi-pi, pi-pi-pi-pi, K anti-K, eta-eta, eta-eta', pi-eta and characteristics of the resonances in the scalar sector, 2) q anti-q nonet classification of scalar bare states, 3) accumulation of widths of the q anti-q states by the glueball due to the overlapping of f_0 resonances at 1200-1700 MeV, 4) systematics of scalar q anti-q states, both bare states and resonances, on the (n,M^2) plots, 5) constraints on the quark-gluonium content of the resonances f_0(980), f_0(1300), f_0(1500), f_0(1750), and the broad state f_0(1420^{+150}_{-70}) from hadronic decays, 6) radiative decays of the P-wave q anti-q resonances: scalars f_0(980), a_0(980), and tensor mesons a_2(1320), f_2(1270), f_2(1525). The analysis proves that in the scalar sector we face two exotic mesons: the light sigma-meson, f_0(450), and the broad state f_0(1420^{+150}_{-70}), which is the descendant of the glueball.

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