Wɔ Black Hills ase bepɔw mile baako ase no, nyansahufo reyɛ nneɛma akɛse a wɔde hwehwɛ neutrino nneɛma mu – na ebia wobenya nea ɛkyerɛ asetra mu asɛm no ho mmuae
Mfe mpem bi a atwam no, mine kurow a wɔfrɛ no Lead, a ɛwɔ South Dakota Black Hills no, atwetwe adwumayɛfo a wɔpɛ sika kɔkɔɔ. Afei de, nhwehwɛmu titiriw bi a wɔreyɛ no wɔ mine dedaw no mu no retwetwe nyansahufo a wɔrehwehwɛ ahonyade a ɛyɛ anigye kyɛn saa: mmuae a ɛfa amansan mu ahintasɛm a emu dɔ no ho.
Deep Underground Neutrino Experiment (Dune) no si wɔ Homestake mine dedaw no mu no bɛfi ase Dwoada. Mfiridwuma adwumayɛfo bɛfi ase bɛboaboa adwinnade akɛse anan ano wɔ abodan a wɔde abotan a ɛwɔ fam kwansin biako no abobɔ ano no mu.
Sɛ wɔsɔ no wɔ nkyɛn a, nea ɛhwɛ no bɛhyerɛn na akyɛman komm bere a ntitimu nketenkete a wɔfrɛ wɔn neutrinos betwa mu fa mu no. Ebi befi owia ne supernovae a ɛwɔ akyirikyiri aba, afoforo nso wɔ hann a emu yɛ den a wɔfaa abotan bɛyɛ anammɔn ɔpepem 800 (kilomita 1,300) mu de fii aban nhwehwɛmu dan a ɛbɛn Chicago, Illinois somae.
Sɛ yɛbɛhwɛ neutrino no a, ebetumi ayi nyansapɛ foforo koraa adi na ama ewiem anwanwade ahorow, te sɛ nsoromma wu ne black hole awo, ada adi. Nyansahufo no ani da so kɛse sɛ wobesiesie abɔde mu nsɛm a ɛbɛkyɛ sen biara no mu baako: dɛn nti na biribiara a atwa yɛn ho ahyia no yɛ ade a wɔde ayɛ (matter) na ɛnyɛ ne “bɔne hemmaa” no, antimatter. Sɛ yɛbɛka no foforo a, dɛn nti na yɛn, na dɛn nti na biribiara, wɔ ha koraa.
"Ɛyɛ bere a ɛyɛ anigye kɛse sɛ yɛreyɛ eyi ho adwuma," saa na Dr Kate Shaw, nea ɔyɛ experimental particle physicist a ɔwɔ Dune a ofiri University of Sussex no kaa. "Neutrinos nkɔ mu nti ara ne nimdeɛ, na ebetumi abue ɔpon ama physics foforo."
Neutrinos ne nneɛma mu nkɛtɛwa a ɛdɔɔso sen biara wɔ amansan yi mu, a photons nko ara na ɛboro wɔn so, a ɛyɛ hann nkɛtɛwa a enni nkaatua a ɛma hann hyerɛn amansan yi mu. Wɔyɛ wɔn wɔ nuclear nneyɛe a ɛfi abɔde mu, te sɛ nea ɛma owia yɛ adwuma no mu, wɔ radioactive porɔwee ne particle accelerators mu.
Mpo wɔ mfiridwuma mufo nhwɛso so no, neutrinos yɛ nneɛma a ɛyɛ nwonwa. Nneɛma kakra a enni mfanu yi ne nneɛma foforo nni biribi mu kakra: bɛyɛ trilliyɔn baako na ɛfa wo nipadua mu a wonhu wɔ anibere biara mu. Neutrinos ba sɛso mmiɛnsa, a ne nyinaa wɔ kuku a esua papa nanso ɛsonosono. Wɔ anwonwakwan so no, wɔsesa fi su biako mu kɔ foforo mu, adeyɛ a wɔfrɛ no oscillation, bere a wɔretu kwan no. “Ɛyɛ suban a ɛyɛ nwonwa yiye,” Shaw na ɔkae. “Ɛte sɛ nea meto aprɛ no ma wo na ɛdan kwadu.”
Lead wɔ abakɔsɛm bi a ɛfa saa afrɛfrɛ nketenkete yi ho. Wɔ 1960 mfe mu no, physicist Ray Davis dii mmoarofo akyi kɔɔ tokuru no mu na ɔde tank bi a ɛkura dry-cleaning nsu gallon 100,000 no yɛɛ detector bi. Esiane sɛ wɔabɔ ho ban wɔ fam akyirikyiri nti, detector no bɛyɛɛ nea edi kan a ɛkyeree neutrinos a efi owia mu bere a wɔbɔɔ chlorine atoms a ɛwɔ nsu no mu na ɛdan wɔn argon no.
Famu no too mu wɔ afe 2001 na ɛnam adwenem adehunu a ɛkɔ anim ho adwuma so, ɛsesaa kɔyɛɛ asasepɛn ase nnwumam adwuma a wɔde ho ama no, Sanford Underground Research Facility (Surf). Ɛhɔ na Lux-Zeplin (LZ) nhwehwɛmu no wɔ dadaw a ɔsram a etwaa mu no ɔbɔɔ amaneɛ a edi kan a ɛfa esum mu ade a ebia wohuu no ho.
"Yɛafiri Asase no mu adeɛ tutuo so akɔ nyansahufoɔ a yɛboa wɔn ma wɔkɔhwehwɛ amansan no mu," saa na Robin Lucero, Lead kuropɔn no sohwɛfoɔ a n'abusua atena beae hɔ awoɔ ntoatoasoɔ pii no kaeɛ. "Yɛ ani gye na yɛanya tiri nkwa sɛ Dune resi ha, ne Surf, a ɛwɔ nhwehwɛmu afoforɔ te sɛ LZ. Nyansahu a ɛkorɔn wɔ wiase nyinaa mu de hokwan foforɔ, nnipa foforɔ ne akwannya foforɔ brɛ yɛn mpɔtam hɔ adwumayɛfoɔ ne titiriw yɛn mmabunu."
Nsonsonoeɛ a ɛda Davis n'adwinnadeɛ ne Dune nhwehwɛmu no ntam no, Dune deɛ no kɛseɛ paa. Wɔde dadeɛ a ɛboro tɔn 4,000 na ayɛ no, deɛ ɛhunu nneɛma no bɛgyina soro akɔsi abrannaa anum, na afa liquid argon a ne nyinaa yɛ tɔn 70,000 a ɛsɛ sɛ wɔma ɛyɛ nwunu kɔsi -200C. Deɛ ɛhunu nneɛma no bɛboaboaano no bɛfa bɛyɛ mfeɛ mmiɛnsa. Sɛ wɔde liquid argon bɛhyɛ mu a, ɛbɛfa afe foforɔ.
“Eyi yɛ adwumayɛ a emu yɛ den a wɔde mfiri ho nimdeɛ di dwuma,” ne nkabom a wɔne mpɔtam hɔ adwumayɛfoɔ a wɔwɔ nimdeɛ ayɛ, saa na Prof David Newbold a ofiri UK Science and Technology Facilities Council a ɔyɛ Dune ho kasamafoɔ no kaeɛ. “Ɛte sɛ hyɛn a wɔreyɛ wɔ asase ase.” UK yɛ ɔhokafoɔ a ɔso sene biara wɔ amanaman ntam wɔ nhwehwɛmu a US di anim yi mu, na ɔreyɛ detector afaahorow atitiriw, komputa adwuma a ɛho hia a wɔde bɛsan asi nsɛm a asisi wɔ detector no mu, ne graphite target a ɛho hia na wɔde ayɛ neutrinos wɔ Femilab, particle physics beaeɛ a ɛwɔ Illinois no.
Sɛ ɛhyɛ ase yɛ adwuma a, Dune bɛhwehwɛ neutrinos nkanea a emu yɛ den a wɔde fi Fermilab mena faa asase so akyi ne ne mu bɛ mail 800. Neutrinos no mu dodow no ara bɛtow afa mu tee, nanso bere biara no, baako bɛpɛm argon atom bi, na ama kanea asra na ɔtɔ a ɛyɛ wɔ mframa mu abɛba. Wei a wobɛhwehwɛ mu no bɛda nsɛm titiriw a ɛfa nneɛma kumaa a ɛyɛ nwonwa no ho adi.
Asɛmmisa kɛse baako fa neutrino ahorow no mu duru ho. Ɛhefa na ɛyɛ hare na ɛhefa na emu yɛ duru? Mmuae no betumi ada ɔbɔadeɛ mu tumi foforo a ɛyɛ nnaadaa adi. Na wɔ mmɔdenbɔ a wɔbɔ sɛ wobebua matter ne antimatter ho asɛmmisa no mu no, Dune bɛhwehwɛ nsonsonoe nketewa a ɛda neutrino ne ne antimatter ntafowemma, antineutrino, ntam.
Wɔ atiafuo akuwakuw a wɔde fi Fermilab bɛba no akyi no, Dune nso bɛhwehwɛ neutrinos a wɔfi wimhyɛn mu reba, a wɔde nsɛm foforo a ɛfa nsoromma a ɛpae ne nnaadaa anim (black holes) nhyehyɛe ho rebɛka ho asɛm.
Ɔbosome yi mfiase no, Nobel abasobɔdeɛ a ɛfa physics ho no hyɛɛ Belgia nhwehwɛmufo Francis Halzen anuonyam, a ɔde Antarctica cubic kilometre baako yɛ adwuma de hwehwɛɛ ahoɔden kɛse neutrinos a efi ɔsoro akyirikyiri. Nanso sɛ wobehu no a, ɛnyɛ asɛm no awiei koraa. "Eyi bɛyɛ sika kɔkɔɔ bere ampa," Newbold kae. "Nea aka a ɛte saa no dɔɔso a ɛreba."
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