Measurements of theDsJResonance Properties

Abstract

We report measurements of the properties of the D sJ 2317 and D sJ 2457 resonances produced in continuum e e ÿ annihilation near s p 10:6 GeV. The analysis is based on an 86:9 fb ÿ1 data sample collected with the Belle detector at KEKB. We determine the masses to be M D sJ Belle [7]. This has led to speculation that the new D s 0 resonances, which we denote D sJ , may be exotic mesons [8][9][10][11][12][13]. Measurements of the D sJ quantum numbers and branching fractions (particularly those for radiative decays) will play an important role in determining the nature of these states.In this Letter we report measurements of the D sJ masses, widths, and branching fractions using a sample of e e ÿ ! c c c events collected with the Belle detector [14] at the KEKB collider [15].We reconstruct D s mesons using the decay chain D s ! and ! K K ÿ . To identify kaons or pions, we form a likelihood for each track, L K , from dE=dx measurements in a 50-layer central drift chamber, the responses from aerogel threshold Č erenkov counters, and time-of-flight scintillation counters. The kaon likelihood ratio, P K= L K = L K L , has values between 0 (likely to be a pion) and 1 (likely to be a kaon).For ! K K ÿ candidates we use oppositely charged track pairs where one track has P K= > 0:5 and the other has P K= > 0:2, and with a K K ÿ invariant mass that is within 10 MeV=c 2 2:5 of the nominal mass. We define the helicity angle H to be the angle between the direction of the K and the D s in the rest frame. For signal events this has a cos 2 H distribution, while for background it is flat; we require j cos H j > 0:35.We reconstruct D s candidates by combining a candidate with a candidate, which is a charged track with P K= < 0:9, and requiring M to be within Fig. 1(a) To study the expected signal shape and detection efficiencies, and to determine the level of cross-feed between the two states, we use a Monte Carlo (MC) simulation that treats the D sJ 2317 as a scalar particle with mass 2317 MeV=c 2 decaying to D s 0 and the D sJ 2457 as an axial-vector particle with mass 2457 MeV=c 2 decaying to D s 0 . Zero intrinsic width is assigned to both states. We find that the D sJ 2317 produces a peak of width 7:1 0:2 MeV=c 2 in the M D s 0 distribution at its nominal mass, and a broader reflection peak (of width 12:3 1:8 MeV=c 2 ) at a mass of 8 MeV=c 2 above the D sJ 2457 peak. This latter peak corresponds to a D s and 0 from a D sJ 2317 decay that are combined with a random photon that passes the jM D s ÿ M D s j < 15 MeV=c 2 requirement. (We refer to this as ''feed-up background.'') The D sJ 2457 produces a peak of width 6:0 0:2 MeV=c 2 at its nominal mass and a broader peak (of width 19:5 3:6 MeV=c 2 ), also at its nominal mass. The latter peak is due to events in which the photon from D s ! D s is missed, and a random photon is reconstructed in its place (referred to as the ''broken-signal background''). In addition, the D sJ 2457 produces a reflection in the D s 0 mass distribution with width 14:9 0:8 MeV=c 2 at a mass of 4 Me...

Masses and decay constants of the Ds0*(2317) and DBali1, Collins2, Cox3 et al. 2017Phys. Rev. D105131611View full textAdd to dashboardCite

“…However, while quark models [4,5] and a number of early lattice calculations [6][7][8][9] based on quark-antiquark interpolators predicted the 0 + state to be a broad resonance above the nearby DK threshold, the experiments observed a narrow state of mass 2317 MeV, 40 MeV below threshold. The detection of another narrow state just below the D * K threshold, the D s1 (2460) [10][11][12] with J P = 1 + , presented a similar puzzle. The strange-charm meson sector can be interpreted within heavy quark effective theory [13][14][15][16][17][18] (HQET).…”

Production of the Ds0(2317) and Ds1(

“…Nowadays it is also well established in the PDG [1] with quantum numbers I(J P ) = 0(1 + ). The mass and width of the D * s0 and D * s1 states reported by the above collaborations [3][4][5][6][7][8][9] are consistent with each other, i.e., The large disagreement between the quark model expectations [2] and the experimental measurements [3][4][5][6][7][8][9] made it difficult to assign these two states as conventional charmedstrange mesons. Since the masses of the D * s0 and D * s1 are about 40 MeV below the DK and D * K thresholds, respectively, many studies proposed that the D * s0 and D * s1 are S -wave DK and D * K molecular states.…”

“…The charmed-strange meson D * s0 was first observed by the BaBar collaboration as a narrow peak in the D s π invariant mass distribution [3]. The state was shortly confirmed by CLEO [4] and Belle [5,6] collaborations. Nowadays it is well established in the PDG [1] with quantum numbers I(J P ) = 0(0 + ).…”

“…The present knowledge about the D * s0 and D * s1 was obtained from the e + e − collision [3][4][5][6][7][8][9]. Thus, it will be helpful to understand the nature of the D * s0 and D * s1 if we can observe them in other production processes.…”

“…Therefore, it is interesting to study the D * s0 and D * s1 productions in the K − p → Λ c D * s0 and K − p → Λ c D * s1 reactions. Since there exist plenty of experimental information about the K p elastic interaction in the energy region relevant to the D * s0 and D * s1 production [3][4][5][6][7][8][9], the effect from the K p initial state interaction (ISI) can be taken into account in order to make a more reliable prediction. This paper is organized as follows.…”