Ukutyhila iMfihlakalo yeMatter-Antimatter Asymmetry yeNdalo yonke kunye neNeutrino Oscillation Experiments

T2K, isiseko eside i-neutrino Uvavanyo lwe-oscillation eJapan, kutshanje lunike ingxelo ngoqwalaselo apho baye bafumanisa ubungqina obuqinileyo bomahluko phakathi kweempawu ezisisiseko zendalo. neutrinos kunye naleyo ye-antimatter ehambelana nayo, i-anti-neutrinos. Olu qwalaselo lunika ingcebiso ekucaciseni eyona mfihlakalo inkulu yenzululwazi-ingcaciso yolawulo lwenzululwazi. kungakhathaliseki kwi Ehlabathini phezu kwe-antimatter, kwaye ke ngoko ubukho bethu.

The kungakhathaliseki-antimatter asymmetry ye Ehlabathini

Ngokutsho kwethiyori yeCosmology, amasuntswana kunye ne-antiparticles yawo yaveliswa ngababini ukusuka kwimitha ngexesha leBig-Bang. I-Antiparticles zi-antimatters ezineepropathi zomzimba eziphantse zifane nezazo kungakhathaliseki amaqabane okt amasuntswana, ngaphandle kwentlawulo yombane kunye neempawu zemagneti ezijikwa umva. Nangona kunjalo, i Ehlabathini ikhona kwaye yenziwe yinto kuphela ebonisa ukuba enye into-antimatter symmetry yaphulwa ngexesha leBig-Bang, ngenxa yokuba izibini azikwazanga ukutshabalalisa ngokupheleleyo ukuvelisa ukukhanya kwakhona. Iingcali zeFiziksi zisakhangela iisayinwe zokuphulwa kwe-CP-symmetry, ezinokuthi zichaze into ephukileyo-i-antimatter symmetry ekuqaleni. Ehlabathini.

I-CP-symmetry yimveliso yee-symmetries ezimbini ezahlukeneyo - i-charge-conjugation (C) kunye ne-parity-reversal (P). I-Charge-conjugation C xa isetyenziswe kwi-particle-charged-particle itshintsha isibonakaliso sentlawulo yayo, ngoko ke i-particle ene-positively charged iba yi- negative-charged kunye ne-vice-versa. Iingqungquthela ezingathathi hlangothi zihlala zingatshintshi phantsi kwesenzo se-C. I-Parity-reversal symmetry iguqula i-spatial coordinates ye-particle esebenza kuyo - ngoko i-particle-right hand iba yi-left-hand, efana nento eyenzekayo xa umntu emi phambi kwesibuko. Ekugqibeleni, xa i-CP isebenza kwi-particle enecala elibi, iguqulwa ibe yinto ekhohlo i-positively-charged, eyi-antiparticle. Ngaloo ndlela kungakhathaliseki kunye ne-antimatter zinxulumene enye kwenye nge-CP-symmetry. Yiyo loo nto i-CP kufuneka yaphulwa ukuze kuveliswe okuqatshelweyo into-antimatter asymmetry, eyaqala ukuchazwa nguSakharov ngowe-1967 (1).

Ekubeni umxhuzulane, i-electromagnetic kunye nokusebenzisana okunamandla akuguquguqukiyo phantsi kwe-CP-symmetry, indawo ekukuphela kwayo yokujonga ukwaphulwa kwe-CP kwiNdalo kukwimeko yee-quarks kunye / okanye iileptons, ezinxibelelana ngokusebenzisana okubuthathaka. Ukuza kuthi ga ngoku, ukwaphulwa kwe-CP kulinganiswe ngokuvavanywa kwicandelo le-quark, nangona kunjalo, incinci kakhulu ukuvelisa i-asymmetry eqikelelweyo ye Ehlabathini. Ke ngoko ukuqonda ukwaphulwa kwe-CP kwicandelo le-lepton kunomdla okhethekileyo kwiiFiziksi ukuqonda ubukho Ehlabathini. I-CP-ulwaphulo-mthetho kwicandelo le-lepton ingasetyenziselwa ukuchaza umcimbi-antimatter asymmetry ngokusebenzisa inkqubo ebizwa ngokuba yi-leptogenesis (2).

Kutheni iineutrinos zibalulekile?

Neutrinos ngawona mancinci, amasuntswana amakhulu eNdalo anombane onguziro. Ukungathathi hlangothi kombane, neutrinos azikwazi ukuba nonxibelelwano lwe-electromagnetic, kwaye azinakho ukusebenzisana okunamandla. I-neutrinos zineenki ezincinci zolandelelwano lwe-0.1 eV (~ 2 × 10-³⁷kg), kungoko intsebenziswano yomxhuzulane ibuthathaka kakhulu. Indlela yodwa neutrinos inokunxibelelana namanye amasuntswana kungenxa yonxibelelwano olubuthathaka olufutshane.

Le propati ebuthathaka-esebenzisanayo ye neutrinos, nangona kunjalo, ibenza babe uphando olunomdla ukufunda izinto ezikude. Ngelixa iifotoni zinokufihlwa, zisasazeke kwaye zisasazwe luthuli, amasuntswana erhasi kunye nemitha yelanga ekhoyo kwi-interstellar medium, neutrinos inokudlula ngokungathintelekiyo kwaye ifikelele kwii-detectors eziseMhlabeni. Kwimeko yangoku, ukuba buthathaka-ukusebenzelana, i-neutrino-icandelo linokuba ngumviwa osebenzayo ukuba afake isandla kwi-CP-violation.

I-Neutrino oscillation kunye ne-CP-yaphulwa

Zintathu iindidi ze-neutrinos (𝜈) – 𝜈_𝑒, 𝜈_𝜇 kunye 𝜈_𝜏 – enye inxulunyaniswa nelepton flavour nganye i-electron (e), muon (𝜇) kunye ne-tau (𝜏). I-neutrinos ziveliswa kwaye zichongwe njenge-flavour-eigenstates ngobudlelwane obubuthathaka ngokudibana ne-lepton ehlawuliweyo yencasa ehambelanayo, ngelixa zisasazeka njengezizwe ezinobunzima obuqinisekileyo, obubizwa ngokuba yi-mass-eigenstates. Ngaloo ndlela umqadi we-neutrino wencasa eqinisekileyo kumthombo uba ngumxube wazo zontathu iincasa ezahlukeneyo kwindawo yokubhaqwa emva kokuhamba ngobude bendlela ethile-inxalenye yencasa eyahlukeneyo ithi ixhomekeke kwiiparamitha zenkqubo. Lo mcimbi waziwa ngokuba yi-neutrino oscillation, eyenza la masuntswana amancinane akhetheke kakhulu!

Ithiyori, nganye ye-neutrino flavour-eigenstates inokubonakaliswa njengendibaniselwano yomgca kuzo zonke ezintathu ze-mass-eigenstates kunye ne-vice-versa kwaye ukuxuba kunokuchazwa nge-matrix ehlangeneyo ebizwa ngokuba yi-Pontecorvo-Maki-Nakagawa-Sakata (PMNS) matrix (3,4) ,3). Le matrix ye-XNUMX-dimensional unitary mixing matrix inokuthi i-parametrized ngama-angles amathathu okuxuba kunye nezigaba ezinzima. Kwezi zigaba zintsonkothileyo, i-neutrino oscillation inovakalelo kwisigaba esinye kuphela, esibizwa ngokuba 𝛿_𝐶𝑃, kwaye ngumthombo owodwa wokuphulwa kwe-CP kwicandelo le-lepton. 𝛿_𝐶𝑃 inokuthatha naliphi na ixabiso kuluhlu −180 ° kunye ne-180 °. Ngexesha 𝛿_𝐶𝑃=0,±180° kuthetha ukuba i-neutrinos kunye ne-antineutrinos ziziphatha ngokufanayo kwaye i-CP igcinwe, 𝛿_𝐶𝑃= ± 90 ° ibonisa ukuphulwa okukhulu kwe-CP kwi-lepton-icandelo loMgangatho oMgangatho. Naliphi na ixabiso eliphakathi libonisa ukuphulwa kwe-CP kwiidigri ezahlukeneyo. Kungoko umlinganiselo we 𝛿_𝐶𝑃 yenye yezona njongo zibalulekileyo zoluntu lwe-neutrino physics.

Umlinganiselo weeparamitha ze-oscillation

I-neutrinos ziveliswa ngobuninzi ngexesha leentshukumo zenyukliya, njengezo zeLanga, ezinye iinkwenkwezi kunye ne-supernovae. Zikwaveliswa kwiatmosfera yoMhlaba ngokusebenzisana kwemitha ye-cosmic ene-energy ephezulu kunye ne-atomic nuclei. Ukuba nombono we-neutrino flux, malunga ne-100 yetriliyoni edlulayo kuthi rhoqo ngomzuzwana. Kodwa asiyiqondi nokuba inxibelelana ngendlela ebuthathaka kakhulu. Oku kwenza umlinganiselo weempawu ze-neutrino ngexesha lemifuniselo ye-neutrino oscillation ibe ngumsebenzi onzima ngokwenene!

Ukulinganisa la masuntswana anzima, ii-neutrino detectors zinkulu, zinekhilo-toni zobunzima kwaye imifuniselo ithatha iminyaka eliqela ukufikelela kwiziphumo ezibalulekileyo ngokwezibalo. Ngenxa yentsebenziswano yabo ebuthathaka, kwathatha izazinzulu malunga neminyaka engama-25 ukubona i-neutrino yokuqala ngokomfuniselo emva kokuba u-Pauli ethumele ubukho bayo ngo-1932 ukucacisa ugcino lwe-energy-momentum kwi-nuclear beta decay (eboniswe kumfanekiso (5)).

Izazinzulu zilinganise zonke ii-engile zokuxuba ezingaphezulu kwe-90% echanekileyo kwi-99.73% (3𝜎) ukuzithemba (6). Ii-engile ezimbini zokuxuba zinkulu ukuchaza i-oscillations ye-solar neutrinos ye-atmospheric, i-engile yesithathu (ebizwa ngokuba 𝜃₁₃) lincinci, ixabiso elilelona lilingana ne-8.6°, kwaye lilinganiswe ngokomfuniselo kutsha nje ngo-2011 ngumfuniselo wereactor neutrino iDaya-Bay eTshayina. Kwi-matrix ye-PMNS, isigaba 𝛿_𝐶𝑃 ibonakala kuphela kwindibaniselwano yesono𝜃₁₃𝑒^{±𝑖𝛿_𝐶𝑃,} ukwenza umlinganiselo wovavanyo we 𝛿_𝐶𝑃 Kunzima.

Iparamitha ebala umyinge wolwaphulo-mthetho lwe-CP zombini kwiquark kunye ne-neutrino-icandelo libizwa ngokuba yi-Jarlskog invariant 𝐽_𝐶𝑃 (7), owona msebenzi wokuxuba ama-angles kunye nesigaba sokuphulwa kwe-CP. Kwicandelo lequark 𝐽_𝐶𝑃~3×10^-5 , ngelixa icandelo le-neutrino 𝐽_𝐶𝑃~0.033 isono𝛿_𝐶𝑃, kwaye ngoko ke inokuba nemiyalelo emithathu yobukhulu enkulu kuno 𝐽_𝐶𝑃 kwicandelo lequark, kuxhomekeke kwixabiso 𝛿_𝐶𝑃.

Iziphumo ezivela kwi-T2K-ingcebiso ekusombululeni imfihlakalo ye-asymmetry ye-matter-antimatter

Kuvavanyo olude lwesiseko se-neutrino oscillation T2K (i-Tokai-to-Kamioka eJapan), imiqadi ye-neutrino okanye i-antineutrino yenziwa kwi-Japan Proton Accelerator Research Complex (J-PARC) kwaye ifunyenwe kwi-Water-Cerenkov detector kwi-Super-Kamiokande, emva kokuhamba umgama oyi-295km ukudlula eMhlabeni. Kuba esi sikhawulezisi sinokuvelisa imiqadi nokuba yeyiphi na 𝜈_𝜇 okanye i-antiparticle yayo 𝜈̅𝜇, kwaye umtshina unokubona 𝜈_𝜇,𝜈_𝑒 kunye ne-antiparticles yazo 𝜈̅𝜇, 𝜈̅𝑒, zineziphumo ezivela kwiinkqubo ezine ezahlukeneyo ze-oscillation kwaye zinokwenza uhlalutyo ukuze zifumane imida esebenzayo kwiiparamitha ze-oscillation. Nangona kunjalo, isigaba sokwaphulwa kwe-CP 𝛿_𝐶𝑃 ibonakala kuphela kwinkqubo xa i-neutrinos itshintsha incasa okt kwi-oscillations 𝜈𝜇→𝜈𝑒 kunye 𝜈̅𝜇→𝜈̅𝑒 - nawuphi na umahluko kwezi nkqubo zimbini unokuthetha ukunyhashwa kwe-CP kwicandelo le-lepton.

Kunxibelelwano lwakutsha nje, intsebenziswano ye-T2K ichaze imida enomdla malunga nokuphulwa kwe-CP kwicandelo le-neutrino, ukuhlalutya idatha eqokelelwe ngexesha le-2009 kunye ne-2018 (8). Esi siphumo sitsha sikhuphe malunga nama-42% awo onke amaxabiso anokubakho e-𝛿_𝐶𝑃. Okubaluleke ngakumbi, imeko xa i-CP igcinwe ikhutshwe kwi-95% yokuzithemba, kwaye ngexesha elifanayo ukuphulwa okukhulu kwe-CP kubonakala kukhethwa kwiNdalo.

Kwinkalo yefiziksi yamandla aphezulu, ukuzithemba kwe-5𝜎 (okt 99.999%) kuyafuneka ekubangeni into entsha, ngoko ke imifuniselo yesizukulwana esilandelayo iyafuneka ukufumana izibalo ezaneleyo kunye nokuchaneka okuphezulu kokufunyanwa kwesigaba sokwaphulwa kwe-CP. Nangona kunjalo iziphumo ze-T2K zakutsha nje luphuhliso olubalulekileyo ekuqondeni kwethu umba we-antimatter asymmetry ye Ehlabathini ngokuphulwa kwe-CP kwi-neutrino-sector, okokuqala ngqa.

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Iingxelo:

1. Sakharov, Andrei D., 1991. '' Ukwaphulwa kwe-CP invariance, i-C asymmetry, kunye ne-baryon asymmetry yendalo yonke ''. ISoviet Physics Uspekhi, 1991, 34 (5), 392-393. DOI: https://doi.org/10.1070/PU1991v034n05ABEH002497

2. Bari Pasquale Di, 2012. Intshayelelo ye-leptogenesis kunye neempawu ze-neutrino. I-Contemporary Physics Volume 53, 2012 - Issue 4 amaphepha 315-338. DOI: https://doi.org/10.1080/00107514.2012.701096

3. UMaki Z., uNakagawa M. kunye noSakata S., 1962. Amanqaku ngomzekelo odibeneyo wamasuntswana asisiseko. Inkqubela phambili yeFiziksi yethiyori, uMqulu wama-28, iNkupho yesi-5, ngoNovemba ka-1962, amaphepha 870–880, DOI: https://doi.org/10.1143/PTP.28.870

4. I-Pontecorvo B., 1958. IINKQUBO ZE-BETA EZIGQIBELEYO KUNYE NOKUNGENAKULONDOLOZA KWE-LEPTON CHARGE. Ijenali yoMfuniselo kunye neTheory Physics (USSR) 34, 247-249 (ngoJanuwari, 1958). Iyafumaneka kwi-intanethi http://www.jetp.ac.ru/cgi-bin/dn/e_007_01_0172.pdf. Ifikeleleke nge-23 ka-Epreli 2020.

5. Inductiveload, 2007. Beta-minus Decay. [umfanekiso kwi-intanethi] Iyafumaneka e https://en.wikipedia.org/wiki/File:Beta-minus_Decay.svg. Ifikeleleke nge-23 ka-Epreli 2020.

6. Tanabashi M., et al. (Iqela leDatha yeNkcazo), 2018. I-Neutrino Mass, Ukuxuba, kunye ne-Oscillations, i-Phys. I-Rev. D98, 030001 (2018) kunye nohlaziyo lwe-2019. DOI: https://doi.org/10.1103/PhysRevD.98.030001

7. Jarlskog, C., 1986. UJarlskog Uyaphendula. I-Phys. Umfundisi Lett. 57, 2875. DOI: https://doi.org/10.1103/PhysRevLett.57.2875

8. I-T2K Collaboration, 2020. Ukunyanzeliswa kwi- matter–antimatter symmetry-violating phase kwi-neutrino oscillations. Umthamo wendalo 580, amaphepha339–344(2020). Ipapashwe: 15 April 2020. DOI: https://doi.org/10.1038/s41586-020-2177-0

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