1129

˙ ஊ࿩ࣨ

CERN Summer Student Programme 2021 ࢀՃใࠂ౦‫ژ‬େֶେֶӃཧֶ‫ڀݚܥ‬Պ෺ཧֶઐ߈म࢜ 1 ೥ࣇ‫ ۄ‬কഅ
shoma@hep.phys.s.u-tokyo.ac.jp
2021 ೥ (ྩ࿨ 3 ೥) 10 ݄ 20 ೔͸͡Ίʹ

12021 ೥ 6 ݄ 28 ೔͔Β 8 ݄ 27 ೔·ͰɼCERN (virtual)
Summer Student Programme ʹࢀՃͨ͠ɻ࢒೦ͳ͕ΒΦϯϥΠϯͰͷ։࠵ͱͳΓ‫ݱ‬஍΁ߦ͘͜ͱ͸Ͱ͖ͳ͔ͬ

2.3‫ڀݚ‬ࢲ͸લड़ͷ௨Γ LHCb ࣮‫ݧ‬άϧʔϓʹ഑ଐ͞Εɼࢦಋ‫׭ڭ‬ͷ Guy Wormser ࢯͷ΋ͱ Run2 ͷσʔλΛ༻͍ͯɼ͕ͨɼߨٛɾ‫ͱڀݚ‬΋ʹඇৗʹີ౓ͷೱ͍࣌ؒΛա͝−+−+−+
Λ0b → Λ+(1)c + π + π + π ; Λc → p + K + π͢͜ͱ͕Ͱ͖ͨɻࢲ͸ LHCb ࣮‫ʹݧ‬഑ଐ͞ΕɼLeptonͱ͍͏෺ཧϞʔυͷ Branching Ratio Λ‫ٻ‬ΊΔղੳΛ

Universality Violation ʹؔΘΔ‫ܞʹڀݚ‬ΘΔ͜ͱ͕Ͱߦͬͨɻ͖ͨɻ͜͜Ͱ͸‫׆‬ಈ಺༰΍‫͍ͯͭʹͱͨ͜͡ײ‬ใࠂ͢Δɻ

LHCb ࣮‫ݧ‬͸ CERN ͷ Large Hadron Collider(LHC)ͷিಥ఺ͷ 1 ͭʹҐஔ͢Δ࣮‫͋Ͱݧ‬ΔɻLHCb ࣮‫ݧ‬ͷ໨2‫׆‬ಈ಺༰త͸ bottom, anti-bottom ΫΥʔΫΛ‫ؚ‬Ήཻࢠͷ่յΛ

2.1ߨٛ

ͷͰ͋Δ [1]ɻ

‫ه‬࿥͠ղੳΛߦ͏͜ͱͰ͋Δɻ‫ݕ‬ग़‫ث‬͸ਤ 1 ͷΑ͏ͳ΋ϓϩάϥϜͷ࠷ॳͷ 5 िؒ͸‫ݱ‬஍࣌ؒͷ‫ޕ‬લதʹϥΠϒͷߨٛɼ‫ ʹޙޕ‬Q&A session ͕͋ͬͨɻ‫ޕ‬લதͷϥΠϒत‫ྫ͕ۀ‬೥ΑΓ΋‫ݮ‬Β͞Ε͍ͯΔΒ͘͠ɼͦͷ෼ͷิ‫ޙޕͯ͠ͱ׬‬ͷ͕࣌ؒઃ͚ΒΕ͍ͯͨɻQ&A session͸ɼࣄલʹ 2 ೥લͷत‫ۀ‬ͷө૾Λ‫ݟ‬Δ͜ͱΛਪ঑͞Εɼͦͷ಺༰Λ‫ߦʹݩ‬ΘΕͨɻͦͷͨΊɼશͯͷत‫ۀ‬Λࢹௌ͢Δͱྫ೥ΑΓ΋ॆ࣮͍ͯͨ͠ͷͩͱࢥ͏ɻ಺༰͸ૉཻࢠ෺ཧֶΛ͸͡Ίɼ౷‫ܭ‬ɾՃ଎‫ث‬෺ཧɾӉ஦࿦ɾҩֶԠ༻ͱଟ‫ʹذ‬Θ͓ͨͬͯΓɼඇৗʹ෯޿͍෼໺ʹֶ͍ͭͯͿ͜ͱ͕Ͱ͖ͨɻQ&A session ͸ɼ࢘ձऀ͕ࢭΊͳ͍ͱऴΘΒͳ͍͜ͱ͸௝͘͠ͳ͘ɼΦϯϥΠϯͳ͕Β‫ʹൃ׆‬ਤ 1: LHCb ࣮‫ݧ‬ͷ‫ݕ‬ग़‫ث‬ߦΘΕ͍ͯͨɻ

2.2‫ֶݟ‬‫ࢪڀݚ‬ઃͷதΛ‫ͯݟ‬ճΔ virtual visit ͕Կ౓͔ߦΘΕͨɻΦϯϥΠϯͳ͕Βਓ਺ΛߜΓෳ਺ճʹ෼͚ͯߦ͍ɼҰਓҰਓͷ࣭໰ʹஸೡʹ౴͍͑ͯͨͷ͕ҹ৅తͰ͋ͬͨɻ

2.3.1

ಈ‫ػ‬

LHCb ࣮‫࠷͍͓ͯʹݧ‬ऴతʹ‫ٻ‬Ί͍ͨ஋ͷ 1 ͭʹҎԼͷΑ͏ͳ΋ͷ͕͋Δɻ

R(Λc ) =−Br(Λ0b → Λ+c τ ν̄τ )+ −0Br(Λb → Λc μ ν̄μ )(2)Lepton Universality ΛԾఆ͠ τ ͱ μ ͷ࣭ྔͷҧ͍Λআ͚͹ɼ͜Ε͸ 1 ʹͳΔ͸ͣͰ͋Δɻ࣮‫Ͱݧ‬͸ R(Λc ) ͷ−−→ 3πντ )෼ࢠΛ‫ٻ‬ΊΔͨΊʹɼBr(Λ0b → Λ+c τ ν̄τ ; τ2130ͱ͍͏ϞʔυΛ༻͍Δ༧ఆͰ͋Δɻ͜ͷϞʔυʹର͢Δෆ͔֬͞Λ‫ݮ‬Βͨ͢Ίʹɼऴঢ়ଶͷϋυϩϯ͕ಉ͡Ͱ͋ΔผͷϞʔυͱͷൺK(Λc ) =−−→ 3πντ )Br(Λ0b → Λ+c τ ν̄τ ; τ+0Br(Λb → Λc 3π)(3)Λ༻͍ͯ஋ΛಘΔɻͦ͜Ͱ͜ͷ K(Λc ) ͷ෼฼ͷ஋ͷਖ਼֬ͳཧղ͕ඞਢͱͳΔɻϓϩάϥϜͰ͸ LHCb ࣮‫ݧ‬ͷσʔλΛ༻͍ͯ͜ͷ K(Λc ) ͷ෼฼Λ‫ٻ‬Ίͨɽ

2.3.2ํ๏
ਤ 2: LHCb ࣮‫ݧ‬ͷ‫ݕ‬ग़‫ʹث‬ೖࣹ͢Δཻࢠͷൺɻ෼฼σʔλΑΓɼΠϕϯτ਺ͷൺ
+− +#(Λ0b → Λ+c 3π; Λc → pK π )0∗∗−#(B → D 3π; D → K π + π + )͸ fd + fu ͭ·Γ LHCb ࣮‫ݧ‬ͷ‫ݕ‬ग़‫ʹث‬ೖࣹ͢ΔϘτ(4)ϜΫΥʔΫΛ‫ؚ‬Ήϋυϩϯͷ͏ͪμ΢ϯΫΥʔΫͱΞοϓΫΥʔΫΛ‫ؚ‬Ή B தؒࢠͷׂ߹Λද͍ͯ͠ΔɻΞΠΛಘΔ͜ͱ͕Ͱ͖ΔɻͦΕͧΕͷϞʔυ͸Πϕϯτͷ७ιεϐϯରশੑΛԾఆ͢Δͱ fB 0 = fd = fu ͱͳΔɻ౓ΛߴΊΔͨΊɼ༷ʑͳτϦΨʔ͕༻͍ΒΕɼ·ͨɼ༷ʑfΛ0b ͸ಉ༷ʹ Λ0b ͷׂ߹Λද͍ͯ͠Δɻfs ͸ετϨϯδͳΧοτ͕͔͚ΒΕ͍ͯΔɻ͜ΕΒͷ‫ܥ‬౷‫ࠩޡ‬Λ‫ੵݟ‬΋
Δඞཁ͕͋Δɻ·ͨΠϕϯτ਺͸γάφϧΛϑΟοτͯ͠‫ٻ‬ΊΔͨΊɼͦͷ‫ܥ‬౷‫ࠩޡ‬΋‫ੵݟ‬΋Δඞཁ͕͋Δɻ
ࣜ (4) Ͱࣔͨ͠ൺ͸− +fΛ0b�Λ0Br(Λ0b → Λ+Br(Λ+c 3π)
c → pK π )×× b×0∗∗−++Br(B → D 3π) fB 0 Br(D → K π π ) �B 0(5)ͱ౳͘͠ͳΔɻ͜͜ͰͦΕͧΕͷཻࢠͷ‫ݕ‬ग़ޮ཰ �Λ0b ͱ

�B 0 ͸ϞϯςΧϧϩγϛϡϨʔγϣϯʹΑͬͯಘΔ͜ͱ͕Ͱ͖Δɻ
·ͨɼLHCb-PAPER-2018-050[2] ʹ͓͍ͯ LHCb ࣮ΫΥʔΫΛ‫ؚ‬Ή B தؒࢠͷׂ߹Λද͍ͯ͠Δɻࠓճ͸fΛ0b /(fd + fu ) ͷ෼෍Λ༻͍ͨɻ• ϞϯςΧϧϩͷ౷‫ྔܭ‬• τϦΨʔͷิਖ਼• ཻࢠࣝผͷิਖ਼• Λ0b ͱ B 0 ͷੜ੒਺ͷൺ• Br(B − → μD0 ν)• Br(B 0 → D∗ 3π)‫ݧ‬ͷ‫ݕ‬ग़‫ʹث‬ೖࣹ͢Δ B 0 ͱ Λ0b ͷൺ͕ͦΕͧΕͷཻࢠγάφϧͷબ୒ʹؔͯ͠͸ɼγάφϧͷ७౓Λ্͛Δͷӡಈྔͷؔ਺ͱͯ͠ਤ 2 ͷΑ͏ʹ‫͍ͯͬ·ٻ‬Δɻͳ͓ɼͨΊʹ࢖ΘΕ͍ͯΔ༷ʑͳΧοτͷ͏ͪɼ࠷΋ෆఆੑ͕− +্‫ه‬ͷҾ༻‫Ͱݩ‬͸ Br(Λ+c → pK π ) ͷ஋΋‫ٻ‬Ί͓ͯେ͖͍Χοτʹؔ͢Δύϥϝʔλͷ஋ΛมԽͤͯ͞ΈͯɼΓɼBr(B 0 → D∗ 3π)ɼBr(D∗ → K − π + π + ) ͸‫ٻʹط‬Ͳͷఔ౓มԽ͢Δ͔ͷͦͷׂ߹Λ‫ܥ‬౷‫ͨ͠ͱࠩޡ‬ɻ·͍ͬͯΔ [3] ͜ͱ͔Βɼ࣮‫ʹݧ‬Αͬͯ 2 ͭͷϞʔυͷμϦπ࠶ॏΈ෇͚ (Dalitz reweighting) ͱ͸ɼ࣮σʔൺΛ‫͢ࢉܭ‬Δͱ Br(Λ0b → Λ+c 3π) ͕‫ٻ‬ΊΒΕΔɻ͜͜Ͱ0∗∗− + +λͱϞϯςΧϧϩͷग़ྗ͕ए‫ׯ‬ҟͳΔ͜ͱΛิਖ਼͢ΔཻͨࢠΛͳΔ΂͘ଗ͑Δ͜ͱͰɼ‫ݕ‬ग़‫ث‬༝དྷͷෆ͔֬͞Λ− +ͨμϦπ࠶ॏΈ෇͚͸ Λ+c → pK π ͷμϦπϓϩοτ

B → D 3π; D → K π π Λ༻͍ͨͷ͸ɼऴঢ়ଶͷΊʹ༻͍ΒΕ͍ͯΔ࠶ॏΈ෇͚ख๏Ͱ͋Δɻࠓճ࢖༻͠‫ݮ‬Βͨ͢ΊͰ͋ΔɻΛ΋ͱʹ࡞੒͞Εͨ΋ͷͰɼਤ 3 ͷΑ͏ʹ pK ͷෆม࣭ྔ෼෍͕σʔλΛ࠶‫͢ݱ‬ΔΑ͏ʹϞϯςΧϧϩΛิਖ਼͠

2.3.3‫ܥ‬౷‫ࠩޡ‬͍ͯΔɻ͜Εʹؔ͢Δ‫ܥ‬౷‫ࠩޡ‬͸ɼద༻લ‫ޙ‬ͷσʔλ਺ͷมԽͷׂ߹Λ༻͍ͨɻࠓճͷ‫࠷Ͱڀݚ‬΋ࠔ೉Ͱ͋ͬͨ఺͸ɼ‫ܥ‬౷‫ࠩޡ‬ͷ‫ੵݟ‬͞ΒʹσʔλͱϞϯςΧϧϩΛҰகͤ͞ΔͨΊɼΛ0b΋ΓͰ͋ΔɻҎԼͷ‫ੵݟ͍ͯͭʹݯࠩޡ‬΋ΓΛߦͬͨɻͷӡಈྔΛ༻͍ͯ࠶ॏΈ෇͚Λߦͳͬͨɻ͜Ε΋ద༻લ• γάφϧͷબ୒• μϦπ࠶ॏΈ෇͚ (Dalitz reweighting)• Λ0b ͷӡಈྔ• Λ∗c ͷআ‫ڈ‬• γάφϧͷϑΟοςΟϯά‫ޙ‬ͷσʔλ਺ͷࠩΛ‫ܥ‬౷‫ͨ͠ͱࠩޡ‬ɻଓ͍ͯߦͳͬͨͷ͕ Λ∗c ͷআ‫ؔ͢ʹڈ‬Δ‫ܥ‬౷‫ࠩޡ‬ͷ‫ੵݟ‬΋ΓͰ͋Δɻ͜ΕΛআ͘ͷ͸ɼ࠷ऴతʹಘ͍ͨ Br(Λ0b →−Λ+c τ ν̄τ ) ʹ͸ Λc ͷྭ‫ى‬ঢ়ଶ͕ଘࡏ͠ͳ͍ͨΊͰ͋Δɻ

3131

ਤ 3: pK ͷ࣭ྔ෼෍ɻσʔλ఺͸‫ࠩޡ‬๮ͱͱ΋ʹࣔ͠ਤ 5:͍ͯΔɻബ͍փ৭ (྘) ͕ॏΈ෇͚͢ΔલͷϞϯςΧϧ

Σc (2455)0 ͷྭ‫ى‬ঢ়ଶͰ͋Δɻϩɼೱ͍փ৭ (੺) ͕ॏΈ෇͚‫ޙ‬ͷϞϯςΧϧϩͷ෼෍

∗
0MΛ +
͸
− − MΛ+ ͷ࣭ྔࠩ෼෍ɻΣc (2520)c πcΛද͍ͯ͠Δɻ

Λ0b → Λ+c 3π ʹ͸ 4 ͭͷதؒঢ়ଶ͕ଘࡏ͢Δɻ+ −Λ0b → Λc (2595)+ π; Λc (2595)+ → Λ+c π π+ −
Λ0b → Λc (2625)+ π; Λc (2625)+ → Λ+c π π−
Λ0b → Σc (2455)0 ππ; Σc (2455)0 → Λ+c π+
Λ0b → Σc (2455)++ ππ; Σc (2455)++ → Λ+c π͜ΕΒΛऔΓআͨ͘Ίʹෳ਺ͷํ๏Λࢼ͠ɼͦͷࠩΛ‫ܥ‬౷‫ੵݟͯ͠ͱࠩޡ‬΋ͬͨɻ࣮ࡍʹ͸্ 2 ͭʹؔͯ͠͸ਤ 4 ͷΑ͏ͳඇৗʹ៉ྷͳϐʔΫ͕‫ݟ‬ΒΕΔͷͰ͜ͷ෦෼ΛऔΓআ͚͹ྑ͘ɼԼ 2 ͭʹ͍ͭͯ‫ੵݟ‬΋ΓΛߦͳͬͨɻͪ͜Βʹؔͯ͠͸ɼਤ 5ɼਤ 6 ͷΑ͏ʹͳ͓ͬͯΓɼ‫ܥ‬౷‫ࠩޡ‬ͷ‫ੵݟ‬΋Γ͕ඞཁͰ͋Δɻͳ͓ਖ਼֬ੑΛߴΊΔͨΊɼ่յ෯͕େ͖͘෼෍ʹେ͖͘Ө‫ڹ‬Λ༩͑Δ Λ+c ͷ࣭ྔΛࠩ͠Ҿ͍͍ͯΔɻ∗++ਤ 6: MΛ+͸
+ − MΛ+ ͷ࣭ྔࠩ෼෍ɻΣc (2520)c πcΣc (2455)++ ͷྭ‫ى‬ঢ়ଶͰ͋ΔɻϝλʔΛ‫ݻ‬ఆͯ͠ϑΟοτͨ͠Γͯ͠ɼͲͷఔ౓ͷมԽ͕‫ݟ‬ΒΕΔ͔Λࢼͨ͠ɻ݁ՌɼόοΫάϥ΢ϯυͷؔ਺ΛมԽͤͨ͞ͱ͖ʹσʔλ਺ͷ‫ੵݟ‬΋Γʹେ͖͘Ө‫͕ڹ‬͋ͬͨͨΊɼ͜ͷ࣌ͷσʔλ਺ͷมԽ෼Λ‫ܥ‬౷‫͠ͱࠩޡ‬ͨɻϑΟοςΟϯάͷ݁Ռ͸ਤ 7 ͷΑ͏ͳ΋ͷͰ͋ΔɻϞϯςΧϧϩͷ౷‫ʹྔܭ‬༝དྷ͢Δ‫ܥ‬౷‫ࠩޡ‬͸౷‫ ྔܭ‬N√ʹରͯ͠ 1/ N Ͱ‫ੵݟ‬΋ͬͨɻτϦΨʔͷิਖ਼ʹؔͯ͠΋ɼෳ਺ͷτϦΨʔͷࠩΛ࠶ॏΈ෇͚ͱͯ͠༻͍ͯͦͷมԽΛ‫ݟ‬Δ͜ͱʹΑΓɼ‫ܥ‬౷‫ͨ͠ͱࠩޡ‬ɻཻࢠࣝผʹؔ͢Δ‫ܥ‬౷‫ࠩޡ‬͸ɼऴঢ়ଶͷཻࢠΛͰ͖Δ͚ͩಉ͡ʹͳΔΑ͏ʹϞʔυΛબͿ͜ͱʹΑͬͯଧͪফ͠߹͏Α͏ʹ͍ͯ͠Δɻ۩ମతʹ͸ɼࠓߟ͍͑ͯ

+ਤ 4: MΛ+ͷํ
+ − − MΛ+ ͷ࣭ྔࠩ෼෍ɻΛc (2595)c π πc0∗+
Δͷ͸ Br(Λ0b → Λ+c 3π)/Br(B → D 3π) ͰɼΛc ͸p, K − , π + ɼD∗ ͸ K − , π + , π + ʹ่յ͢ΔϞʔυͰ͋Δɻʹ͸ผͷΧοτ͕͔͚ΒΕ͓ͯΓϐʔΫ͕খ͘͞ͳͬͯ

͔͠͠ཅࢠͷΈ͕ࠩग़͖ͯͯ͠·͏ͷͰɼͦͷཻࢠࣝผ͍Δɻ

ʹؔ͢Δ‫ܥ‬౷‫ࠩޡ‬Λ‫ੵݟ‬΋ͬͨɻ͜͜Ͱ͸ɼཅࢠͷӡಈྔͳͲΛ༻͍͍͔ͨͭ͘ͷ࠶ॏΈ෇͚Λ͠ɼͦͷࠩΛ‫ܥ‬γάφϧͷϑΟοςΟϯάʹؔͯ͠͸όοΫάϥ΢ϯ
υͷؔ਺Λมߋͨ͠Γɼ͍͔ͭ͘ͷϑΟοςΟϯάύϥ

౷‫ੵݟͯ͠ͱࠩޡ‬΋ͬͨɻ

Λ0b ͱ B 0 ͷੜ੒਺ͷൺʹ༝དྷ͢Δ‫ܥ‬౷‫ࠩޡ‬͸ LHCb-4132

Events / ( 4 MeV/c2 )Λc 3 π mass
2000

31800
16001400

ϓϩάϥϜதͷੜ‫׆‬alpha = 1.85 ± 0.24

Dataࠓճ͸ΦϯϥΠϯ։࠵ͱͳΓ೔ຊࠃ಺͔ΒͷࢀՃͱ

Signal + Backgroundc = -0.01597 ± 0.0021

Gaussian signal

frac_g1 = 0.0326 ± 0.0049

CB signal

mu = 5619.34 ± 0.12 MeV/c2

Exponential backgroundn = 3.0 ± 3.0ͳͬͨɻͦͷͨΊલ൒͸ඇৗʹଟ๩Λ‫ۃ‬Ίͨɻ·ͨ࣌ࠩnBkg = 724 ± 219

1200

ͷ౎߹Ͱ‫ޕ‬લ 2 ࣌ఔ౓·Ͱؔ࿈͢Δߨٛ౳͕͋Γɼͦͷ

nSig = 18604 ± 212

1000

sigma1 = 31.1 ± 4.5 MeV/c2800

ͳͬͨͨΊɼେֶͷत‫ۀ‬΋్த·Ͱड͚ͳ͕ΒͷࢀՃͱ

sigma2 = 14.07 ± 0.11఺͸࢓ํͳ͍͕͖͍ͭͱ‫͡ײ‬Δ͜ͱ΋͋ͬͨɻ΍͸Γɼ

600

͔ͤͬ͘ͷ‫ػ‬ձͰ͋ͬͨͷͰ‫ݱ‬஍ʹ଍Λӡͼ͔ͨͬͨͱ

400

͍͏ͷ͕ਖ਼௚ͳͱ͜ΖͰ͋Δɻ200
5500

5520

5540

5560

5580

5600

5620

5640

5660
5680
5700
m(Λ c3π) [MeV/c2]

4ࠓ‫ޙ‬ͷ๊ෛͱϓϩάϥϜʹ๬Ή͜ͱਤ 7: Λ0b ͷ࣭ྔ෼෍ɻσʔλ਺ͷ‫ੵݟ‬΋Γ͸͜ͷΑ͏ͳϑΟοςΟϯάΛ༻͍ͯߦΘΕͨɻࠓճͷ‫ֶͰڀݚ‬Μͩ஌ࣝ΍ٕज़Λࠓ‫ޙ‬ͷࣗ෼ͷ‫ʹڀݚ‬

PAPER-2018-050 ͔Β fΛ0b /fB 0 Λӡಈྔͷؔ਺ͱͯ͠
ࢉग़͠ɼࣗ෼͕ಘͨσʔλ਺ͷൺΛ‫ݕ‬ग़ޮ཰Ͱิਖ਼ͨ͠
΋ͷ͔ΒׂΓɼͦͷ݁ՌΛ‫ݟ‬Δ͜ͱͰ‫ੵݟ‬΋ΓΛߦͳͬͨɻ͜Ε͸ɼ‫͍͖͍͔ͨͯ͠׆‬ɻम࢜̍೥ͷஈ֊Ͱಉ͡ૉཻࢠ෼໺ͷผͷ‫ܞʹڀݚ‬ΘΓɼ‫ݟ‬ฉ͕޿·ͬͨͷͰɼࠓ‫ޙ‬΋ੵ‫ۃ‬తʹ͜͏͍ͬͨϓϩάϥϜʹ͸ࢀՃ͍͖͍ͯͨ͠ɻ
ࠓճ͸ίϩφՒͱ͍͏ҟྫͷ։࠵ͩͬͨͷͰ࢓ํͳ͍
෦෼΋͋Δ͕ɼଞͷࢀՃऀͱͷަྲྀ͕΍΍গͳ͔ͬͨͷN (Λ0b → Λ+f 0c 3π)
× B0∗
N (B → D 3π)
fΛ0b͸࢒೦Ͱ͋ͬͨɻւ֎͔ΒࢀՃ͞Ε͍ͯΔਓ͸ඇৗʹଟ‫ʹذ‬ΘͨΔόοΫάϥ΢ϯυΛ͍࣋ͬͯͨΑ͏ʹ‫͡ײ‬Δ

Br(Λ+Br(Λ0b → Λ+c 3π)
c → pKπ)×=0∗
Br(B → D 3π) Br(D∗ → Kππ)(6)ͱͳΓɼӡಈྔґଘੑ͕ͳ͘ͳΔ͜ͱΛར༻͍ͯ͠Δɻ

ͷͰɼͦ͏͍ͬͨਓͱΑΓҰ૚ަྲྀ͕Ͱ͖ͨΒΑ͔ͬͨɻདྷ೥Ҏ߱͸ࣗ෼͸ࢀՃͰ͖ͳ͍͕ɼੋඇର໘Ͱ։࠵͞ΕΔ͜ͱΛ‫͏ئ‬ɻཧ૝తʹ͸ࣜ (6) ͷࠨล͸ͲͷӡಈྔྖҬͷΠϕϯτΛ༻͍ͯ‫ͯ͠ࢉܭ‬΋ಉ͡஋ͱͳΔ͸͕ͣͩɼ࣮ࡍʹ͸ӡಈྔґଘੑΛগ࣋ͬͯ͠͠·͏ͷͰɼͦͷఔ౓Λ‫ܥ‬౷‫ࠩޡ‬ͱͯ͠‫ੵݟ‬΋ͬͨɻͦͷଞͷ෼‫ذ‬ൺʹؔ͢Δ‫ܥ‬౷‫ࠩޡ‬͸ա‫ڈ‬ͷղੳʹΑͬͯ‫ʹط‬ಘΒΕ͍ͯΔ஋Λ༻͍ͨɻ

5ँࣙϓϩάϥϜʹࢀՃ͢Δʹ͋ͨͬͯɼଟ͘ͷํʹ͓ੈ࿩ʹͳΓ·ͨ͠ɻਪનॻΛॻ͍͍͍ͯͨͩͨԣࢁকࢤ‫ڭ‬तɼՖ֞࿨ଇ‫ڭ‬तʹ‫ँײ‬ਃ্͛͠·͢ɻKEK ͷօ༷ʹ͸ࣄ຿खଓ͖΍ͪ͜Β͔Βͷ࣭໰ʹ͓౴͍͖͑ͨͩ·ͨ͠ɻSupervisor ͷ Guy Wormser ࢯʹ͸ϓϩάϥϜ‫ؒظ‬લͷ
2.3.4

݁Ռ4 ݄͔ΒԿ౓΋ΦϯϥΠϯͰ૬ஊʹ৐ͬͯͩ͘͞Γɼॆ࣮ͨ͠ϓϩάϥϜΛૹΔ͜ͱ͕Ͱ͖·ͨ͠ɻ·ͨɼԁ‫׈‬ຊղੳͷ݁ՌɼͳϓϩάϥϜӡӦͷͨΊ༷ʑͳ‫ا‬ըΛ༻ҙͯͩ͘͠͞Γɼ·ͨ‫ݸ‬ผͷ࣭໰ʹ΋ରԠ͍͍ͨͩͨ CERN ͷօ༷ɼಛ− + −Br(Λ0b → Λ+c π π π )= (5.05 ± 0.06(stat.) ± 0.64(syst.)) × 10−3(7)͕ಘΒΕͨɻલड़ͷ௨ΓɼΛ∗c ঢ়ଶΛ‫ܦ‬༝͢Δ΋ͷ͸আ͍͍ͯΔɻ

PDG ʹΑΔͱɼͰ͋Δɻ
ࠓճಘΒΕͨ݁Ռ͸‫ࠩޡ‬ͷൣғ಺ͰҰகͨ͠ɻࢀߟจ‫ݙ‬[1] The LHCb Collaboration and A Augusto Alveset al., JINST 3, S08005 (2008).

− + −∗Br(Λ0b → Λ+c π π π ; without Λc , PDG)

= (6.14 ± 0.94) × 10−3

ʹ Ana Dordevic ࢯʹ͸͓ੈ࿩ʹͳΓ·ͨ͠ɻ(8)[2] The LHCb Collaboration and R. Aaij et al.,Phys. Rev. D 100, 031102 (2019).
[3] Particle Data Group and Zyla, P A etal., Progress of Theoretical and Experimental
Physics 2020, 083C01 (2020).