English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

A constellation of quarkonium-mass peaks has been reported in the lastdecade, opening what could be an entire new spectroscopy of nuclear-physicslike complexity. Salient among these structures are the $Z_c$, much analyzed atBESIII as nicely summarised by J.~Zhao at this conference. Their stature as newhadron states has often been challenged by proposals that the peaks arise fromtriangle singularities instead, because they appear in three-body reactions andoften satisfy the special kinematic conditions of the Coleman-Norton theorem.To experimentally decide, we should like to resort to different reactionserasing the kinematic coincidence, and see whether each peak survives. Weobserve that the most universal "eraser" is the medium created in Heavy IonCollisions, because its high temperature often affects the masses and widths ofthe particles participating in the reaction: if additionally the trianglereaction is completed during the lifetime of the fireball, our computations inthermal field theory show that the triangle singularities do not survive thehot hadron phase (much less the hotter quark-gluon plasma). On the contrary,ordinary quarkonia are affected but often survive the fireball andmolecular-like states are also routinely detected. We have provided severalexamples, and here investigate the exotic $Z_{c}(4020)^\pm\to \pi^{\pm} h_c $peak (produced against a $\pi^\mp$ in $e^+e^-$ collisions). If, as has beenproposed during the debates, it is produced or enhanced by a $D_{1} D^{*} D^*$triangle loop, the estimate here reported suggests its disappearance near thecritical temperature of the confinement/deconfinement phase transition, so anyfuture detection in heavy-ion collision data would suggest it to be a realhadron, with its absence leaning towards the singularity interpretation.

New $Z_c$ spectroscopy or Landau singularities? Searches in Heavy Ion Collisions could help decide