Z_c(3900): What has been really seen?

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• 作者：Miguel Albaladejo^a ; ^{Miguel.Albaladejo@ific.uv.es" class="auth_mail" title="E-mail the corresponding author} ; Feng-Kun Guo^b ; ^c ; Carlos Hidalgo-Duque^a ; Juan Nieves^a
• 刊名：Physics Letters B
• 出版年：2016
• 出版时间：10 April 2016
• 年：2016
• 卷：755
• 期：Complete
• 页码：337-342
• 全文大小：454 K

文摘

The 16001210&_mathId=si1.gif&_user=111111111&_pii=S0370269316001210&_rdoc=1&_issn=03702693&md5=0c2aed1c3f0a1df8ac9c4ea798c26ef6">16001210-si1.gif">$Z_c^{\pm }(3900)/Z_c^{\pm }(3885)$ resonant structure has been experimentally observed in the 16001210&_mathId=si2.gif&_user=111111111&_pii=S0370269316001210&_rdoc=1&_issn=03702693&md5=a6950fddfa7ede6f7500c1d972d7d128" title="Click to view the MathML source">Y(4260)→J/ψππ$Y(4260)\to J/\psi \pi \pi$ and 16001210&_mathId=si3.gif&_user=111111111&_pii=S0370269316001210&_rdoc=1&_issn=03702693&md5=94bbad8164ea34209cb57f4ab34abe2d">16001210-si3.gif">$Y(4260)\to {\overline{D}}^{⁎}D\pi$ decays. This structure is intriguing since it is a prominent candidate of an exotic hadron. Yet, its nature is unclear so far. In this work, we simultaneously describe the 16001210&_mathId=si4.gif&_user=111111111&_pii=S0370269316001210&_rdoc=1&_issn=03702693&md5=b398a12ebbe0882405c643cc0c034f05">16001210-si4.gif">${\overline{D}}^{⁎}D$ and 16001210&_mathId=si27.gif&_user=111111111&_pii=S0370269316001210&_rdoc=1&_issn=03702693&md5=785c5b59cb710bdfdac5ab637705182e" title="Click to view the MathML source">J/ψπ$J/\psi \pi$ invariant mass distributions in which the 16001210&_mathId=si6.gif&_user=111111111&_pii=S0370269316001210&_rdoc=1&_issn=03702693&md5=02bd52f7c400b7b157339c16004ece23" title="Click to view the MathML source">Z_c$Z_c$ peak is seen using amplitudes with exact unitarity. Two different scenarios are statistically acceptable, where the origin of the 16001210&_mathId=si6.gif&_user=111111111&_pii=S0370269316001210&_rdoc=1&_issn=03702693&md5=02bd52f7c400b7b157339c16004ece23" title="Click to view the MathML source">Z_c$Z_c$ state is different. They correspond to using energy dependent or independent 16001210&_mathId=si4.gif&_user=111111111&_pii=S0370269316001210&_rdoc=1&_issn=03702693&md5=b398a12ebbe0882405c643cc0c034f05">16001210-si4.gif">${\overline{D}}^{⁎}D$S  -wave interaction. In the first one, the 16001210&_mathId=si6.gif&_user=111111111&_pii=S0370269316001210&_rdoc=1&_issn=03702693&md5=02bd52f7c400b7b157339c16004ece23" title="Click to view the MathML source">Z_c$Z_c$ peak is due to a resonance with a mass around the 16001210&_mathId=si61.gif&_user=111111111&_pii=S0370269316001210&_rdoc=1&_issn=03702693&md5=98ed3f6aa2a9640bc1bb6bf4a1ccb70c">16001210-si61.gif">$D{\overline{D}}^{⁎}$ threshold. In the second one, the 16001210&_mathId=si6.gif&_user=111111111&_pii=S0370269316001210&_rdoc=1&_issn=03702693&md5=02bd52f7c400b7b157339c16004ece23" title="Click to view the MathML source">Z_c$Z_c$ peak is produced by a virtual state which must have a hadronic molecular nature. In both cases the two observations, 16001210&_mathId=si9.gif&_user=111111111&_pii=S0370269316001210&_rdoc=1&_issn=03702693&md5=bb186b978d1a671f9de6f112b5c31716">16001210-si9.gif">$Z_c^{\pm }(3900)$ and 16001210&_mathId=si10.gif&_user=111111111&_pii=S0370269316001210&_rdoc=1&_issn=03702693&md5=962de7e29b9098324847be1cfabcbc85">16001210-si10.gif">$Z_c^{\pm }(3885)$, are shown to have the same common origin, and a 16001210&_mathId=si4.gif&_user=111111111&_pii=S0370269316001210&_rdoc=1&_issn=03702693&md5=b398a12ebbe0882405c643cc0c034f05">16001210-si4.gif">${\overline{D}}^{⁎}D$ bound state solution is not allowed. Precise measurements of the line shapes around the 16001210&_mathId=si61.gif&_user=111111111&_pii=S0370269316001210&_rdoc=1&_issn=03702693&md5=98ed3f6aa2a9640bc1bb6bf4a1ccb70c">16001210-si61.gif">$D{\overline{D}}^{⁎}$ threshold are called for in order to understand the nature of this state.