NEUTRINO 1,555 DA SUKA ƊAN TURA CIBIYAR ZARRA GABA ƊAYA

Wani lokaci neutrino ba ya bugun ƙwaya ɗaya a cikin zarra, sai dai dukkan cibiyar zarra (nucleus) lokaci ɗaya, wadda ke komawa baya a matsayin dunƙule ɗaya. An yi hasashen wannan “warwatsewa mai haɗaka kuma elastic ta neutrino a kan cibiyar zarra” (coherent elastic neutrino-nucleus scattering) a 1974. Saboda dukkan cibiyar tana shiga ciki, damar karo tana ƙaruwa, don haka na’urorin ganowa masu nauyin ’yan kilogram kawai za su iya ganinsa.

Ƙungiyar COHERENT ce ta fara gano shi, da neutrino daga wani tushen neutron. Manyan na’urorin gano duhun abu (dark matter) su ma sun ba da rahoton shaidarsa da neutrino daga Rana. Reactors na nukiliya wani tushe ne: suna samar da antineutrino masu ƙarancin makamashi, har zuwa kusan electronvolt miliyan 10. Ganowa ta farko a wajen reactor ta fito ne daga CONUS+ kansa, da muhimmanci (significance) na 3.7 σ.

Raɗar makamashi

Matsalar ita ce ƙanƙantar bugun. Antineutrino daga reactor yana sa cibiyar zarrar germanium ta koma baya da ’yan dubban electronvolt a mafi yawa. 15 zuwa 20% ne kawai na wannan makamashi ke juyawa zuwa siginar wutar lantarki da na’urar ganowa za ta iya karantawa. Dukkan abubuwan suna taruwa ne kaɗan sama da mafi ƙarancin makamashin da na’urar za ta iya rubutawa — daidai inda daidaita na’urar (calibration) ya fi wuya.

Na’urar ganowa kusa da zuciyar reactor

CONUS+ yana a tashar wutar lantarki ta nukiliya ta Leibstadt a Switzerland, mita 20.7 daga zuciyar wani reactor da ke samar da gigawatt 3.6 na zafi. Yana aiki tun Nuwamba 2023. Don zagaye na biyu na tattara bayanai, lu’ulu’u biyu mafi girma na germanium tsantsa sosai sun haɗu da ɗaya daga cikin na’urorin ganowa na asali: jimillar kilogram 5.6 na nauyi mai aiki (active mass). Garkuwa mai matsewa ta dalma (lead) da filastik mai ɗauke da boron, na’urar ganowa da ke watsi da (veto) muon na sararin samaniya, da hura iska mara radon ba tsayawa sun rage hayaniyar baya (background) da kusan ninki 10,000.

An tattara bayanai daga Fabrairu 2025 zuwa Yuli 2026: kilogram-rana 1,296 da reactor yana aiki da 86 da yake a tsaye.

Ƙirga a makance

Don guje wa yaudarar kansu, masana kimiyyar lissafin (physicists) sun ɓoye bayanan ƙarancin makamashi yayin da suke shirya nazarinsu, sannan suka bayyana na’urorin ganowa ɗaya bayan ɗaya. Sakamakon: abubuwa 1,555 ± 152. Siginar ta fi rashin tabbacinta girma da ninki 10.2. Standard Model na ilimin ƙwayoyin zarra (particle physics) ya yi hasashen 1,701 ± 198 — yarjejeniya a cikin karkacewar ma’auni (standard deviations) 0.6, da rabon abin da aka auna zuwa abin da aka yi hasashe na 0.91 ± 0.14.

Gwaji mai amfani: da reactor a tsaye, daidaitawar (fit) tana samun abubuwa 22 ± 29, daidai da sifili. Siginar da ba daga reactor ta fito ba da ta ba da kusan 103.

Ƙidaya a cikin na’urorin ganowa uku da reactor yana aiki: siginar neutrino (ruwan lemu) tana saman hayaniyar baya, kaɗan sama da iyakar ganowa (threshold). — Figure 1, CONUS Collaboration (2026), arXiv:2610.37318.

Kamu mafi girma zuwa yanzu

A cewar marubutan, wannan shi ne samfuri mafi girma (largest sample) na irin waɗannan karo da aka taɓa ganowa, kuma ma’auni mafi daidaito a matakan makamashin reactor, da daidaito da ya yi kama da sakamakon COHERENT na baya-bayan nan a kan germanium. Rashin tabbacin ƙidayar yanzu 9.8% ne, kusan ninki uku ƙasa da na zagayen farko.

Ya yi daidai da iyakokin sama (upper limits) da wasu gwaje-gwajen germanium a wajen reactors suka kafa. Akasin haka, siginar da gwajin Dresden-II ya ba da rahoto tana nuna adadi da ya fi girma a fili fiye da waɗanda sauran gwaje-gwajen germanium a wajen reactors suka gani, har da wannan.

Ƙarfin karon idan aka kwatanta da adadin neutron a cibiyar zarrar da aka nufa: CONUS+ (baƙar alamar siffar lu’u-lu’u, germanium) yana kan lanƙwasar reactor (ja). — Figure 3, CONUS Collaboration (2026), arXiv:2610.37318.

Auna ƙarfi mai rauni

A cikin Standard Model, yawan karon yana ƙaruwa da murabba’in “cajin rauni” (weak charge) na cibiyar zarrar:

Q_W = N − (1 − 4 sin²θ_W) Z

inda N da Z su ne adadin neutron da proton ɗinta, θ_W kuma kusurwar haɗuwa ta rauni (weak mixing angle), wani ma’auni na ƙarfin nukiliya mai rauni (weak nuclear force). Daga ƙidayar, ƙungiyar ta sami sin²θ_W = 0.225 ± 0.022, daidai da 0.2387 da ake tsammani. Cikin ma’aunai irin wannan, shi ne ke binciken ƙarfin a mafi ƙarancin canja wurin momentum (momentum transfer).

Ana ci gaba da ƙirga

Ma’aunin har yanzu adadin abubuwan ne galibi ke iyakance shi. Ƙarin shekara ɗaya na bayanai zai sauko da rashin tabbacin ƙididdiga zuwa kusan 5%. Ingantaccen daidaitawa (calibration) a iyakar ganowa da sababbin ma’aunai na yadda germanium ke canza makamashin komawa baya (recoil energy) ya kamata su rage rashin tabbacin hasashen. Marubutan suna ganin neutrino na reactor suna tashi daga ganowa ta farko zuwa ma’auni mai cikakken daidaito.