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SUMMARY:Searching for Strangelets and Macro-SQM Candidates from Neutron St
 ars\, Binary Mergers\, and Gamma-Ray Bursts: Multi-messenger Constraints a
 nd Direct-Detection Prospects
DTSTART;VALUE=DATE-TIME:20261030T093000Z
DTEND;VALUE=DATE-TIME:20261030T094500Z
DTSTAMP;VALUE=DATE-TIME:20261101T090927Z
UID:indico-contribution-6204@cern.ch
DESCRIPTION:Speakers: Chitta Ranjan Das (Bogoliubov Laboratory of Theoreti
 cal Physics (BLTP)\, Joint Institute for Nuclear Research (JINR))\nStrange
  quark matter (SQM) is a compelling candidate for the true ground state of
  quantum chromodynamics (QCD) at high baryon density. Within the Bodmer-Wi
 tten-Terazawa hypothesis\, if SQM has a lower energy per baryon than ordin
 ary hadronic matter\, neutron stars can convert to strange quark stars (SQ
 Ss). Stable clusters of SQM\, strangelets\, can be produced in dense QCD p
 hase transitions\, releasing up to $\\sim10^{53}$ erg. Strangelets consist
  of approximately equal numbers of up\, down\, and strange quarks\; their 
 baryon number $A$ is one third of the total quark number\, and their net e
 lectric charge is $Z$. Both MIT-bag and Nambu-Jona-Lasinio descriptions pr
 edict mass-to-charge ratios $m_S/|Z|\\sim30$ to $60$ GeV/$c^2$ for $A\\sim
 10^{2}$ to $10^{5}$. A key formation channel is the transition from the tw
 o-flavor color-superconducting (2SC) phase to the color-flavor-locked (CFL
 ) phase in dense quark matter. Diquark condensation\, fragmentation of Fer
 mi surfaces\, and surface emission of quark clusters can produce strangele
 ts\, while strangelet-anti-strangelet annihilation\, $S\\bar{S}\\to\\gamma
 \\gamma$\, can generate narrow\, monochromatic very-high-energy (VHE) $\\g
 amma$-ray lines.\n\nThis work develops a unified framework connecting QCD-
 motivated strangelet production to observable multi-messenger fluxes. A ph
 enomenological production-rate model is introduced that balances geometric
  growth\, $\\dot N(A)\\propto (A/A_{\\rm peak})^{2/3}$\, against exponenti
 al suppression from multi-fragmentation and coalescence. The framework is 
 applied to three representative astrophysical environments: (i) HESS J1731
 $-$347\, a steady SQS candidate with $M=0.77^{+0.20}_{-0.17}M_\\odot$ and 
 $R=10.4^{+0.86}_{-0.78}$ km\, whose 2SC-CFL interface can inject strangele
 ts into the surrounding supernova remnant\; (ii) GW170817\, the first bina
 ry neutron-star merger\, where the hadron-to-quark transition in the post-
 merger remnant can produce a burst-like strangelet flux\; and (iii) GRB 25
 0702B\, an ultra-long gamma-ray burst with duration $>25{\,}000$ s and $E_
 {\\rm iso}>1.4\\times10^{54}$ erg\, providing an extreme burst-driven chan
 nel. Constraints from H.E.S.S.\, Fermi-LAT\, MAGIC-II\, and the projected 
 Cherenkov Telescope Array (CTA) are compiled. The baseline scenario lies n
 ear the CTA sensitivity threshold ($\\sim10^{-13}$ ph cm$^{-2}$ s$^{-1}$ a
 t 1 TeV)\; the optimistic scenario is already excluded by H.E.S.S.\, while
  the conservative scenario requires next-generation instruments.\n\nA comp
 lementary direct-detection program targets macroscopic SQM composites such
  as nuclearites and Q-balls. Although microscopic strangelets are unlikely
  to survive interstellar propagation\, these heavier objects possess extre
 mely large mass-to-charge ratios and high ionization densities\, allowing 
 them to traverse the interstellar medium and penetrate the terrestrial atm
 osphere. Their passage would produce bright\, continuous high-ionization t
 racks\, thermal shock fronts\, and slow luminous transits in large-volume 
 detectors. Existing limits from MACRO\, SLIM\, ANTARES\, and IceCube alrea
 dy constrain parts of the parameter space\, while future facilities includ
 ing LHAASO\, KM3NeT/ARCA\, SQM-ISS\, and gravitational-wave observatories 
 will provide complementary sensitivity. Combining narrow VHE $\\gamma$-ray
  line searches with direct macro-SQM detection and multi-messenger follow-
 up of neutron stars\, mergers\, and GRBs offer a decisive test of the stra
 nge quark matter hypothesis.\n\nhttps://indico.particle.mephi.ru/event/626
 /contributions/6204/
LOCATION: Conference Hall 4
URL:https://indico.particle.mephi.ru/event/626/contributions/6204/
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