Dissociation of Quarkonium in a Strong Electric Field
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, PARTICLES, FIELDS, GRAVITATION, AND ASTROPHYSICS
Dissociation of Quarkonium in a Strong Electric Field A. M. Ishkhanyana,b and V. P. Krainovc,* a
b
Institute for Physical Research, National Academy of Sciences of Armenia, Ashratak, 0203 Armenia Institute of Physics and Technology, National Research Center “Tomsk Polytechnic University,” Tomsk, 634050 Russia c Moscow Institute of Physics and Technology, Dolgoprudnyi, Moscow oblast, 141700 Russia *e-mail: [email protected] Received October 20, 2017
Abstract—The probability of tunnel decay of quarkonium (bond state of a heavy quark and a heavy antiquark) into free quarks in a strong electric field is estimated. DOI: 10.1134/S1063776118040039
The interest in the properties of bound states of a pair of heavy quarks (quarkonium) has been revived in recent years. These states are generally analogous in properties to the positronium, viz., the neutral bound state of the electron and the positron. Analogous neutral bound states form two systems: charmonium cc consisting of a charmed quark and antiquark (with charges +2e/3 and –2e/3) and bottomonium bb , consisting of beautiful quark and antiquark (with charges –e/3 and +e/3) [1]. The only difference is that the particles forming positronium are observable, while quarks in free form have never been observed as yet. The exact form of the potential of the interaction between a quark and an antiquark is unknown. There exist different models that describe experimental spectra with the same accuracy. These models include, for example, the Quigg–Rosner potential [2], the Martin potential [3], and the so-called Cornell potential [4] proposed by physicists of the Cornell University (Ithaca, New York, USA). In the case of power-law potentials, the general form of these models is the trinomial
V = Cq + A + Br s , C < 0; q, s, B > 0 r (a logarithmic potential can be treated as the limiting case of this potential for q, s → 0). In this communication, we estimate the probability of electric-field induced tunnel decay of the quarkonium into free quarks. If the electric field potential varies in space in accordance with the power law VE ~ rp with exponent p > s, this field can induce the dissociation of the quarkonium with a certain probability. This occurs, for example, for the Martin potential in a constant electric field, while in the case of the Cornell potential (q = s = 1), the constant field cannot break the quarkonium. The corresponding experiment with the formation of
free quarks in a certain region of space in which the detection is possible could serve as an argument in favor of a certain model. Let us consider the decay of the quarkonium in the Martin model potential [3] of attraction between a heavy quark and an antiquark in their bound state (quarkonium); this potential has the well-known form
V (r ) = A + Br 0.1.
(1)
Here, A = –6.0 GeV, B = 6.87 GeV, and distance r between the quark and the antiquark is measured in GeV–1 (this scale is about 10–3 fermi). These constants are determined from the experimental position
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