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George Rupp

Publications and source records attributed to George Rupp.

At least 73 records · Page 4Linked to original sources
arXiv2009

Production of hadron pairs in electron-positron annihilation near the K(+)K(-), D-Dbar, B-Bbar and Lambda(c)(+)-Lambda(c)(-) thresholds

We study the structures in cross sections and R ratios concerning electron-positron annihilation reactions, for open-strangeness, open-charm and open-beauty hadron-pair production, from the perspective of a recently developed production formalism. Special attention is paid to non-resonant contributions. Known, tentative, and yet unknown resonances are spotted, with estimates for their masses and widths.

hep-ph↗
arXiv2009

The Y(4140), X(4260), psi(2D), psi(4S) and tentative psi(3D)

Data on B+ --> J/psi phi K+ and the Y(4140) enhancement recently reported by the CDF collaboration [arxiv:0903.2229] are analysed. The threshold behaviour, as well as traces of the X(4260) enhancement, the known c-cbar resonances psi(2D), psi(4S), and a tentative psi(3D) state, as observed in the mass distribution, suggest that the J/psi+phi system has quantum numbers JPC=1--. It is then argued that the Y(4140) enhancement does not represent any kind of resonance, but instead is a natural consequence of the opening of the J/psi+phi channel.

hep-ph↗
arXiv2009

Light and Not So Light Scalar Mesons

A multichannel description of the light scalar mesons in the framework of the Resonance-Spectrum Expansion is generalised by including vector-vector and scalar-scalar channels, besides the usual pseudoscalar-pseudoscalar channels. Experimental data for the isoscalar, isodoublet and isovector cases are fitted up to energies well above 1 GeV. The resulting pole positions of the light and intermediate scalar mesons are compared to the listed resonances. Possible further improvements are discussed.

hep-ph↗
arXiv2009

Interference effects in the X(4260) signal

We show that the long known puzzling branching ratios of open-charm decays in electron-positron annihilation can be reasonably described with a simple form factor, which strongly suppresses open channels far above threshold. Application to the electron-positron annihilation into J/psi+pion+pion data on the X(4260) enhancement recently reported by the BABAR Collaboration [arxiv:0808.1543] allows a good fit with a simple nonresonant cusp structure around the D(*)(s)+Dbar(*)(s) threshold. Moreover, we argue that a closer look at the data reveals an oscillatory pattern, which we model as an interference effect between a fast - OZI-allowed - and a slow - OZI-forbidden - J/psi+f(0)(980) mode. Other candidates for similar nonresonant enhancements are discussed.

hep-ph↗
arXiv2009

The X(4260) and possible confirmation of psi(3D), psi(5S), psi(4D), psi(6S) and psi(5D) in J/psi pi+ pi-

Data on e+ e- --> J/psi pi+ pi- and the X(4260) enhancement by the BABAR collaboration [ arXiv:hep-ex/0506081, arXiv:0808.1543 ] are analysed by modelling missing signals that should be present in the complete production amplitude with vector quantum numbers in the charmonium region. Thus, it is shown that the data contain evidence for the existence of the psi(5S), the psi(4D), the psi(6S) and the psi(5D) c-cbar vector states, and furthermore a clear indication for the mass and width of the psi(3D). Moreover, it is shown that signs of the psi(3S), psi(2D) and psi(4S) can be observed in the same data. Finally, it is argued that the X(4260) enhancement is not a resonance, but rather a phenomenon connected with the opening of the D(s)(*)-Dbar(s)(*) threshold and the coupling to the J/psi f(0)(980) channel.

hep-ph↗
arXiv2008

Possible psi(5S), psi(4D), psi(6S) and psi(5D) signals in Lambda(c)-antiLambda(c)

It is shown that the Lambda(c+)-Lambda(c-) signal recently reported by the Belle Collaboration (ARXIV:0807.4458) contains clear signs of the psi(5S) and the psi(4D) c-cbar vector states, and also some indication for the masses and widths of the psi(6S) and psi(5D). Moreover, it is argued that the threshold behaviour of the Lambda(c+)-antiLambda(c-) cross sections suggests the presence of the hitherto undetected psi(3D) state not far below the Lambda(c+)-Lambda(c-) threshold.

hep-ph↗
arXiv2008

Multichannel Description of Light and Intermediate Scalar Mesons

The light scalar mesons in a variety of approaches are briefly reviewed, as well as their description in the Resonance-Spectrum Expansion and related coupled-channel formalisms. A recent multichannel modelling of the light scalars is extended to higher energies and with additional decay channels, allowing to make predictions for the intermediate scalar mesons as well. Prospects for further improvements are discussed. PACS numbers: 14.40.Cs, 14.40.Ev, 11.80.Gw, 11.55.Ds, 13.75.Lb

hep-ph↗
arXiv2008

Comment on "Two-photon decay of the sigma meson"

We comment on a recent paper by Giacosa, Gutsche, and Lyobovitskij, in which it is argued that a quarkonium interpretation of the $σ$ meson should give rise to a much smaller two-photon decay width than commonly assumed. The reason for this claimed discrepancy is a term in the transition amplitude, necessary for gauge invariance, which allegedly is often omitted in the literature, including the work of the present authors. Here we show their claims to be incorrect by demonstrating, in the context of the Quark-Level Linear $σ$ Model, that the recently extracted experimental value $Γ_{σ\to2γ}=(4.1\pm0.3)$ keV is compatible with a $q\bar{q}$ assignment for the $σ$, provided that meson loops are taken into account as well.

hep-ph↗
arXiv2008

The spectrum of charmonium in the Resonance-Spectrum Expansion

We argue that the resonance-like structures Y(4260) (arXiv:hep-ex/0506081,arXiv:0707.2541), Y(4360), Y(4660) (arXiv:0707.3699) and Y(4635) (arXiv:0807.4458), which were recently reported to have been observed in experiment, are non-resonant manifestations of the Regge zeros that appear in the production amplitude of the Resonance-Spectrum Expansion. Charmonium c-cbar states are visible on the slopes of these enhancements.

hep-ph↗
arXiv2008

Meson-meson interactions and Regge propagators

By a reformulation of the loop expansion in the Resonance-Spectrum-Expansion amplitude for meson-meson scattering, in terms of s-channel exchange of families of propagator modes, we obtain a formalism which allows for a wider range of applications. The connection with the unitarized amplitudes employed in some chiral theories is discussed. We also define an alternative for the Regge spectra and indicate how this may be observed in experiment.

hep-ph↗
arXiv2008

Deducing the string-breaking distance in strong production processes

We show that the string-breaking distance can be read from meson-production data, by employing a previously derived expression for the production amplitude. Accordingly, we find that the radii of 0.67, 0.34 and 0.20 fm for the creation of non-strange q-qbar pairs obtained in the Resonance-Spectrum-Expansion model, for light-quark, c-cbar, and b-bbar environments, respectively, are in perfect agreement with S-wave di-pion production data, upon employing an ansatz with no additional free parameters.

hep-ph↗
arXiv2007

Why the Pennington-Wilson expansion with real coefficients is of little use in the analysis of production processes

We critically analyse and comment on the claims of M. R. Pennington and D. J. Wilson [arxiv:0711.3521]. Although we generally agree with their obvious algebra, it is clearly not applicable to our equations. Moreover, we argue that the corresponding proposal is not useful for production-data analysis. The advantages of our approach, which involves complex yet purely kinematical coefficients, are summarised.

hep-ph↗
arXiv2007

The complex relation between production and scattering amplitudes

The unitarity relation, Im(A)=T* A, is derived for a three-body production amplitude, A, that consists of a complex linear combination of elements of the two-body scattering amplitude, T. We conclude that the unitarity relation does not impose a realness condition on the coefficients in the expansion of, A, in terms of, T.

hep-ph↗
arXiv2007

How we discovered the nonet of light scalar mesons

As has been confirmed meanwhile by lattice-QCD calculations (see e.g. hep-lat/0702023), the confinement spectrum of non-exotic quark-antiquark systems has its ground state for scalar mesons well above 1 GeV in the Resonance Spectrum Expansion (RSE). For instance, in the S-wave Kaon-pion RSE amplitude, a broad resonance was predicted slightly above 1.4 GeV [hep-ex/0106077], which is confirmed by experiment as the K*0(1430). However, a complete nonet of light scalar mesons was predicted (Zeit.Phys.C30,615 [http://www-spires.slac.stanford.edu/spires/find/hep?key=1573454]) as well, when a model strongly related to the RSE and initially developed to describe the heavy quarkonia resonance spectra (Phys.Rev.D21,772 [http://www-spires.slac.stanford.edu/spires/find/hep?key=363162]) was applied in the light-quark sector. Thus, it was found that the light scalar-meson nonet constitutes part of the ordinary meson spectrum, albeit represented by "extraordinary" [hep-ph/0701038] poles [hep-ex/0106077]. Similar resonances and bound states appear in the charmed sector [hep-ph/0305035], and are predicted in the B-meson spectrum [hep-ph/0312078, hep-ph/0406242]. A recent work [hep-ph/0703286] confirmed the presence of light scalar-meson poles in the RSE amplitude for S-wave and P-wave pion-pion and Kaon-pion contributions to three-body decay processes measured by the BES, E791 and FOCUS collaborations.

hep-ph↗
arXiv2007

Relating multichannel scattering and production amplitudes in a microscopic OZI-based model

Relations between scattering and production amplitudes are studied in a microscopic multichannel model for meson-meson scattering, with coupling to confined quark-antiquark channels. Overlapping resonances and a proper threshold behaviour are treated exactly in the model. Under the spectator assumption, it is found that the two-particle production amplitude shares a common denominator with the elastic scattering amplitude, besides a numerator consisting of a linear combination of all elastic and some inelastic matrix elements. The coefficients in these linear combinations are shown to be generally complex. Finally, the standard operator expressions relating production and scattering amplitudes, viz. A=T/V and Im(A)=T*A, are fulfilled, while in the small-coupling limit the usual isobar model is recovered.

hep-ph↗
arXiv2007

S-wave and P-wave pion-pion and kaon-pion contributions to three-body decay processes in the Resonance-Spectrum Expansion

We study S- and P-wave pion-pion and kaon-pion distributions for the three-body production processes $J/ψ\toωπ^{+}π^{-}$, $D^{+}\to K^{-}π^{+}π^{+}$, $D^{+}\to K^{+}π^{+}π^{-}$, and $D^{+}_{s}\to K^{+}π^{+}π^{-}$, by applying the Resonance-Spectrum Expansion to the two-body subamplitudes. The results are compared to the corresponding signals reported by the BES, E791 and FOCUS collaborations. We find that the studied S- and P-wave channels can largely account for the observed structures in the data up to 1 GeV.

hep-ph↗