111

˙ ‫঺ڀݚ‬հ

LHC ATLAS Run 2 ࣮‫ݧ‬ͷώοάε࠷৽݁Ռ౦‫ژ‬େֶ ૉཻࢠ෺ཧࠃࡍ‫ڀݚ‬ηϯλʔ໊‫ݹ‬԰େֶ େֶӃཧֶ‫ڀݚ‬Պɹɹ૿ᔹ ୡ໵tatsuya.masubuchi@cern.chງҪ ହ೭yhorii@hepl.phys.nagoya-u.ac.jp

2021 ೥ (ྩ࿨ 3 ೥) 5 ݄ 6 ೔

1

͸͡Ίʹ

2012 ೥ʹώοάεཻࢠ͕ൃ‫͞ݟ‬ΕͯҎདྷ, LHC ATLAS ࣮‫ݧ‬͸σʔλΛண࣮ʹ஝ੵ͍ͯ͠Δɻਤ 1 Ͱࣔ͞Ε͍ͯΔΑ͏ʹ, ॏ৺‫ܥ‬ΤωϧΪʔ 13 TeV Ͱ 2015 ೥͔Β࢝·ͬͨ Run 2 ࣮‫ݧ‬͸, 2018 ೥ʹऴྃ͢Δ·Ͱʹ໿ 147 fb−1 ͷσʔλΛऔಘͨ͠ɻRun 2 ͷ࠷େॠؒϧϛϊγςΟ͸ 2.1 × 1034 cm−2 s−1 ͱઃ‫ܭ‬஋ͷ 2 ഒʹ౸ୡͨ͜͠ͱͰ, ‫ݕ‬ग़‫ث‬ͷӡసʹ͸༷ʑͳࠔ೉͕͕͋ͬͨ,෺ཧղੳʹ͸໿ 139 fb−1 ͷσʔλ͕࢖༻Ͱ͖, ͳΜͱ

95%ͷߴޮ཰Ͱ͢΂ͯͷओཁͳ‫ݕ‬ग़‫͕҆ث‬ఆಈ࡞͍ͯ͠
ͨɻϧϛϊγςΟϨϕϦϯά1 Λ༻͍ͨ҆ఆӡస࣌ͷฏ‫ۉ‬ύΠϧΞοϓࣄ৅਺͸࠷େͰ 60 Λ௒͕͑ͨ, ߴύΠਤ 1: ATLAS Run 2 ࣮‫͚͓ʹݧ‬Δੵ෼ϧϛϊγςΟɻϧΞοϓ‫Ͱڥ؀‬΋τϦΨʔ΍෺ཧΦϒδΣΫτ࠶ߏ੒ͷੑೳΛҡ࣋͢Δ޻෉Λ͍ͭ͘΋ಋೖ͠, ෺ཧ‫΁౓ײ‬ͷӨ༥ ߹ ա ఔ (VBF), ϕ Ϋ λ ʔ Ϙ ι ϯ Λ ൐ ͏ ੜ ੒ ա‫ڹ‬Λ཈͑ͨɻ

ఔ (V H; W H/ZH), τοϓΫΥʔΫରΛ൐͏ੜ੒ա

Run 2 ͷߴ౷‫ܭ‬σʔλΛ༻͍ͯ, ώοάεཻࢠͷੑ࣭ͷਫ਼ີଌఆ͕ਐΜͰ͓Γ, ಛʹώοάεཻࢠͱϑΣϧϛఔ (tt̄H) ͕‫͛ڍ‬ΒΕΔɻͦΕΒͷϑΝΠϯϚϯਤΛ, ਤ 2ʹࣔ͢ɻΦϯͷ૬‫༻࡞ޓ‬ʢ౬઒݁߹ʣ΍ඍ෼அ໘ੵͷਫ਼ີଌఆͰ,ଟ͘ͷॏཁͳϚΠϧετʔϯ͕͋ͬͨɻຊߘͰ͸, ҎલͷߴΤωϧΪʔχϡʔεͰใࠂ͞Εͨ݁Ռ [2] Ҏ߱ͷॏཁͳ݁ՌΛ͍͔ͭ͘঺հ͢ΔɻRun 2 ͷؒʹඇৗʹ୔ࢁͷώοάεଌఆɾ୳ࡧͷ݁Ռ͕ग़͍ͯΔ͕, ͢΂ͯ͸঺հ͖͠Εͳ͍ͷͰ‫ڵ‬ຯ͋Δํ͸ [3] Λ‫ͯݟ‬΋Β͍͍ͨɻ2(a) ggF(b) VBF(c) V H (W H/ZH)(d) tt̄Hώοάεཻࢠͷੜ੒աఔͱ่յ
ඪ४໛‫Ͱܕ‬͸, ώοάε৔ͷରশੑ͕ࣗൃతʹഁΕΔ

͜ͱͰ, ήʔδϘιϯ, ϑΣϧϛΦϯ͕࣭ྔΛ֫ಘ͢Δɻ

LHC Ͱ͸, ෳ਺ͷώοάεཻࢠͷੜ੒աఔ, ่յΛ‫؍‬ଌ͢Δ͜ͱͰ, ͦͷඳ૾Λ‫͖Ͱূݕ‬Δɻ
LHC ʹ ͓ ͚ Δ ώοά ε ཻ ࢠ ͷ ओ ͳ ੜ ੒ ա ఔ ͱ ͯ͠, ά ϧ ʔ Φ ϯ ༥ ߹ ա ఔ (ggF), ϕ Ϋ λ ʔ Ϙ ι ϯ

ਤ 2: ώοάεཻࢠͷੜ੒աఔͷϑΝΠϯϚϯਤɻඪ४໛‫͚͓ʹܕ‬Δੜ੒அ໘ੵΛਤ 3 ʹࣔ͢ɻ࠷΋அ

1 LHC Ͱ͸ϧϛϊγςΟͷ૿ՃͰ‫ݕ‬ग़‫ث‬ͷσʔλऩूʹෛՙ͕͔͔Γ͗͢ͳ͍Α͏ʹ, িಥ࣌ʹ̎ͭͷཅࢠϏʔϜͷ࣠ΛͣΒ͠ͳ͕Β,ϧϛϊγςΟΛίϯτϩʔϧ͢Δ [1]ɻ໘ੵ͕େ͖͍ͷ͸ ggF աఔͰ͋Γ, ώοάεཻࢠ͸͜ͷաఔΛ༻͍ͯൃ‫͞ݟ‬ΕͨɻggF աఔ͸ϧʔϓΛ‫ؚ‬Ήͨ

2

10

1
bb

10-1

pp → qqH (NNLO QCD + NLO EW)-210

pp → WH (NNLO QCD + NLO EW)

1

pp → ZH (NNLO QCD + NLO EW)

10-3

4FS)

pp → tH (NLO QCD)

120

122

WW
gg
ττ
cc
ZZ
γγ

pp → ttH (NLO QCD + NLO EW)
pp → bbH (NNLO QCD in 5FS, NLO QCD in

10−1

LHC HIGGS XS WG 2016

s= 13 TeV

pp → H (N3LO QCD + NLO EW)

Branching Ratioσ(pp → H+X) [pb]102

LHC HIGGS XS WG 2016

12

Zγ
μμ

124

126

10-4
120 121 122 123 124 125 126 127 128 129 130128130MH [GeV]MH [GeV]ਤ 3: ඪ४໛‫͚͓ʹܕ‬Δώοάεཻࢠੜ੒աఔͷஅ໘ਤ 4: ඪ४໛‫͚͓ʹܕ‬Δώοάεཻࢠͷ่յ෼‫ذ‬ൺ [4]ɻ

ੵ [4]ɻॏ৺‫ܥ‬ΤωϧΪʔ 13 TeV ͷཅࢠɾཅࢠিಥʹώοάεཻࢠ࣭ྔ 120–130 GeV ͷൣғͰࣔ͢ɻ

ର͢Δ஋Λ, ώοάεཻࢠ࣭ྔ 120–130 GeV ͷൣғͰ
ࣔ͢ɻ

3.1

τοϓΫΥʔΫ౬઒݁߹ͷ‫؍‬ଌΊ, ώοάεཻࢠͱଞͷཻࢠͷ݁߹ଌఆʹ͸ཧ࿦తԾఆ

ώοάεཻࢠͱτοϓΫΥʔΫͷ౬઒݁߹Λ௚઀ଌఆ͕ೖͬͯ͠·͏͕, ৽ཻࢠ͕ϧʔϓʹ‫د‬༩͢Δ৔߹ʹ৽͢ΔͨΊʹ͸, tt̄H ੜ੒աఔΛར༻͢ΔɻτοϓΫΥʔ෺ཧʹ‫͕͋౓ײ‬ΔՄೳੑ͕͋ΔɻVBF աఔ, W H/ZH

Ϋ͸࣭ྔ͕େ͖͘ώοάεཻࢠͷ่յͰ͸ੜ੒͞Εͳ͍աఔ͸, ώοάεཻࢠͱ W Ϙιϯ, Z Ϙιϯͷ݁߹Λ‫ؚ‬ͨΊ, ଞͷϑΣϧϛΦϯͷ౬઒݁߹ͷ‫ͱূݕ‬͸ҟͳΓ,Ήɻtt̄H աఔ͸, அ໘ੵ͕૬ରతʹখ͍͕͞, ώοάεώοάεཻࢠͷੜ੒աఔΛ༻͍Δඞཁ͕͋ΔɻཻࢠͱτοϓΫΥʔΫͷ݁߹ΛπϦʔϨϕϧͰ௚઀‫؍‬ଌͰ͖Δɻඪ४໛‫͚͓ʹܕ‬Δώοάεཻࢠͷ่յ෼‫ذ‬ൺΛ, ਤ 4tt̄H ੜ੒աఔʹ͓͍ͯ͸, τοϓΫΥʔΫͷ่յͰੜ͡ΔϨϓτϯΛଊ͑ΒΕΔͨΊ, ଟ͘ͷ‫͕ऀڀݚ‬, ෼‫ذ‬ൺ͕େ͖ͳ H → bb̄ ่յΛ༻͍Δղੳʹ‫ظ‬଴ΛࠐΊ͍ͯʹࣔ͢ɻώοάεཻࢠͱϑΣϧϛΦϯͷ݁߹͸, ࣭ྔ͕ͨɻ͔͠͠, tt̄ ʹ෇ਵͯ͠ b ΫΥʔΫ͕ੜ੒͞ΕΔաఔ

େ͖ͳϑΣϧϛΦϯ΄Ͳେ͖͍͕, τοϓΫΥʔΫ͸ॏͷཧ࿦తͳෆఆੑ͕େ͖͘, H → γγ ่յ, H → W W

͗ͯ͢ώοάεཻࢠͷ่յͰ͸ੜ੒͞Εͣ, H → bb̄ ่յ͕࠷΋ߴ͍෼‫ذ‬ൺΛ࣋ͭɻ࣍ʹ่յ෼‫ذ‬ൺ͕େ͖͍ͷ͸, H → W W ่յͰ͋Γ, ยํͷ W Ϙιϯ͸Ծ૝ཻࢠ่յ, H → τ τ ่յʹओ‫؟‬Λஔ͍ͨղੳ͕ΑΓߴ͍୳ࡧ‫౓ײ‬Λఏ‫ͨ͠ڙ‬ɻH → γγ ่յͷղੳʹ͓͍ͯ͸, ऴঢ়ଶͷཻࢠͷ̐‫ݩ‬ӡಈྔΛ‫ػ‬ցֶशͷೖྗม਺ʹ͢ΔͳͲ

ͱͯ͠ੜ੒͞ΕΔɻ͜ΕΒ͓Αͼ H → τ τ ่յ, H → cc̄

ͷղੳख๏ͷվྑʹΑΓ, 36 fb−1 ͷσʔλΛ༻͍ͨղϦʔϨϕϧͷ่յͰ͋Γ, ่յͰੜ੒͞ΕΔཻࢠͱώο50%ͷ‫্޲౓ײ‬Λ࣮‫ͨ͠ݱ‬ɻ͜ͷվྑʹΑΓ, H → γγ่յ, H → ZZ ่յ, H → μμ ่յͳͲ͸, ͦΕͧΕπάεཻࢠͷ݁߹ͷநग़ʹར༻Ͱ͖ΔɻҰํ, H → gg ่յ, H → γγ ่յ, H → Zγ ่յ͸, ϧʔϓΛհ͢Δ่

յͰ͋Δɻ

ੳ͔Β, 80 fb−1 Λ༻͍ͨղੳ·Ͱͷؒʹ, ख๏ͷΈͰ่յΛ༻͍Δղੳ͕ tt̄H ੜ੒୳ࡧͷओ໾ʹ༂Γग़ͨɻ

Run 2 Ͱऔಘͨ͠ 80 fb−1 ͷσʔλΛ༻͍ͨෳ਺ͷղੳΛ౷߹͢Δ͜ͱͰ, ༗ҙ౓ 5.8σ ͕ಘΒΕ, tt̄H ੜ੒աఔͷ৴߸ͷൃ‫ʹݟ‬੒ޭͨ͠ [6]ɻਤ 5 ͸, tt̄H ੜ੒աఔ3౬઒݁߹ͷଌఆ
ඪ४໛‫͍͓ͯʹܕ‬, ώοάεཻࢠͱϑΣϧϛΦϯͷ౬઒݁߹ͷେ͖͞͸, ϑΣϧϛΦϯͷ࣭ྔʹൺྫ͢Δɻ౬઒݁߹ͷେ͖͞Λଌఆ͢Δ͜ͱͰ, ϑΣϧϛΦϯͷ࣭ྔ֫ಘͷඳ૾Λ‫͖Ͱূݕ‬ΔɻRun 1 ͷσʔλΛ༻͍ͨղੳ
Ͱ, λ΢ཻࢠͷ౬઒݁߹͸ 5σ Λ௒͑Δ༗ҙ౓Ͱൃ‫Ͱݟ‬͖ͨ [5]ɻRun 2 Ͱ͸, ଞͷϑΣϧϛΦϯͷ౬઒݁߹ͷൃ‫੾͕ݟ‬๬͞Ε͖ͯͨɻͷ୳ࡧʹ͓͚Δ log10 (S/B) ෼෍Λࣔ͢ɻS ͱ B ͸ҟͳΔ่յʹର͢ΔղੳͰ࢖༻͞Εͨ࠷ऴ෼཭ม਺ͷ֤ϏϯͰͷ৴߸਺ͱഎ‫ࣄܠ‬৅਺Λࣔ͠, log10 (S/B) Ͱࣄ৅Λฒ΂ସ͑Δ͜ͱͰ༷ʑͳ่յʹର͢Δղੳ݁ՌΛҰͭͷϓϩοτͰ౷߹ͯ͠৴߸ͷ௒աΛ‫ݟ‬Δ͜ͱ͕Ͱ͖Δɻੜ੒
அ໘ੵͱ่յ෼‫ذ‬ൺͷੵͷඪ४໛‫ܕ‬ͷ஋ʹର͢Δൺʢ৴
+0.21

߸‫ ౓ڧ‬μʣ͸ μ = 1.32 ± 0.18 (stat.)−0.19 (syst.) ͱಘΒΕͨʢਤ 6ʣɻRun 2 Ͱऔಘͨ͢͠΂ͯͷσʔλΛ༻͍ͨղੳ΋ਐΜͰ͓Γʢਤ 7ʣ [7, 8, 9], ͢΂ͯͷ݁Ռ͕,

313

ਤ 6: tt̄H ੜ੒աఔͷ୳ࡧʹ͓͚Δ৴߸‫౓ڧ‬ʢμ =SM
σttH /σttHʣͷଌఆ݁Ռɻώοάεཻࢠͷ่յ͝ͱͷ݁Ռ͓Αͼ౷߹݁ՌΛࣔ͢ɻਤ 5: tt̄H ੜ੒աఔͷ୳ࡧʹ͓͚Δ log10 (S/B) ෼෍ɻԼͷύωϧ͸σʔλͱഎ‫ࣄܠ‬৅ͷൺΛ͍ࣔͯ͠Δɻ࣮ઢ
ʢ఺ઢʣ͸, ώοάεཻࢠͷ৴߸Λ μ = 1.32 (1.0) ʹ‫֨ن‬Խͨ͠ͱ͖ʹ༧૝͞ΕΔ෼෍Ͱ͋Δɻඪ४໛‫͚͓ʹܕ‬ΔτοϓΫΥʔΫͷ࣭ྔ֫ಘͷඳ૾Λࢧ͍࣋ͯ͠Δɻ

3.2

ϘτϜΫΥʔΫ౬઒݁߹ͷ‫؍‬ଌ͓ͦΒ͘ LHC Ͱ‫؍‬ଌͰ͖Δώοάεཻࢠͱμ΢ϯλΠϓΫΥʔΫͷ૬‫༻࡞ޓ‬͸, ϘτϜΫΥʔΫͱͷ૬‫࡞ޓ‬༻͚ͩͰ͋Γ, ͦͷ௚઀ଌఆ͸ඪ४໛‫ܕ‬ͷ‫ূݕ‬ͷ্ͰඇৗʹॏཁͰ͋Δɻ·ͨ, ࠷େͷ่յ෼‫ذ‬ൺΛ࣋ͭͨΊώοάεϘιϯͷ่յ෯ʹ੍‫ݶ‬Λ༩͑Δ͜ͱ͕Ͱ͖Δɻલճͷ঺հͰ͸, Run 2 ʹ͓͍ͯ 2016 ೥·Ͱʹऔಘͨ͠σʔλ໿ 36 fb−1 Λ༻͍ͯಘͨ 3.5σ ͷஹީΛใࠂ [2] ͕ͨ͠, ղੳͷ೉͔͠͞Β‫؍‬ଌ͕ࠔ೉Ͱ่յ෼‫ذ‬ൺ͕࠷େʹ΋ؔΘΒͣ “ൃ‫ʹ ”ݟ‬͸ࢸΒͳ͔ͬͨɻ͢Ͱʹ‫ܥ‬౷‫ࠩޡ‬͕ࢧ഑తʹͳΓͭͭ͋Γ, ൃ‫͚ͯ޲ʹݟ‬͸σʔλΛ૿΍͚ͩ͢Ͱͳ͘‫ܥ‬౷‫ࠩޡ‬ͷ࡟‫ݮ‬΋ඞཁͰ͋ͬͨɻ
‫؍‬ଌ͞ΕΔ৴߸͸ώοάεཻࢠ͔Β่յͨ͠ೋͭͷ bδΣοτͷͨΊ, ੜ੒அ໘ੵ͕େ͖͍ ggF ΍ VBF ੜ੒աఔͰ͸‫͍ڧ‬૬‫༻࡞ޓ‬༝དྷͷഎ‫ࣄܠ‬৅ (pp → bb̄) ͕ଟ͘,‫౓ײ‬Λग़͢ͷ͕೉͍͠ɻͦͷͨΊ, W H/ZH ੜ੒աఔͰ୳ࡧΛߦ͏ͷ͕ԦಓͰ͋Δɻ͜ͷੜ੒աఔͰ͸, ϕΫλʔϘιϯͷϨϓτχοΫ่յΛ࢖͏͜ͱͰ, Ϩϓτϯ΍ফࣦԣӡಈྔτϦΨʔͰ৴߸Λޮ཰Α͘औಘ͠, എ‫ܠ‬ࣄ৅Λେ͖͘࡟‫͢ݮ‬Δ͜ͱ͕ՄೳͰ͋ΔɻW H/ZH ੜ੒աఔͷऴঢ়ଶͷϨϓτϯͷ਺ʹΑͬͯղੳΛ 0/1/2 ϨϓτϯͷΧςΰϦʔʹ෼͚ͯࣄ৅બ୒Λ࠷దԽ͠, ೋͭͷ b λά͞ΕͨδΣοτΛཁ‫͢ٻ‬Δɻഎ‫ࣄܠ‬৅Λ‫ݮ‬Β͢ਤ 7: tt̄H, H → γγ ͷ୳ࡧʹ͓͚Δ γγ ෆม࣭ྔͷϑΟοτ݁ՌɻσʔλʢΤϥʔόʔ෇͖υοτʣ, ϑΟοτ݁Ռʢ࣮ઢʣΛࣔ͢ɻͨΊʹϕΫλʔϘιϯͷԣӡಈྔ͕ߴ͍ࣄ৅Λબ୒͠,bb ෆม࣭ྔ෼෍ͳͲ৴߸ͷಛ௃ྔΛ‫ػ‬ցֶशʹೖΕΔ
͜ͱͰ, ߋʹഎ‫ࣄܠ‬৅ͷ෼཭ೳྗΛվળ͢Δɻ

2017 ೥·Ͱͷ໿ 80 fb−1 ͷσʔλΛ༻͍ͨղੳͰ,V H, H → bb̄ ͷ༗ҙ౓͸ 4.9σ ʢඪ४໛‫ܕ‬ΛԾఆͨ͠ͱ

͖ͷ‫ظ‬଴஋ 5.1σ ʣʹ౸ୡͨ͠ʢਤ 8ʣɻ·ͨ, ώοάεཻࢠ͕ bb̄ ่յ͢Δଞͷੜ੒աఔͷ݁Ռ΋౷߹͢Δͱ‫ײ‬౓͸ 5.4σ ʹ౸ୡ͠, ώοάεཻࢠͱϘτϜΫΥʔΫ͕݁߹͢Δ৽͍͠૬‫༻࡞ޓ‬ΛॳΊͯ‫؍‬ଌ͢Δ͜ͱʹ੒ޭ͠
ͨɻ·ͨ, ‫؍‬ଌͨ͠৴߸‫౓ڧ‬͸ඪ४໛‫͍ྑͱܕ‬ҰகΛ͍ͯͨ͠ [10]ɻਤ 9 ͸ bb ෆม࣭ྔ෼෍Λ͓ࣔͯ͠Γ, ‫ػ‬ցֶशΛ༻͍ͳ͍γϯϓϧͳղੳͰ΋, 125 GeV ͱແໃ६ͳώοάεཻࢠͷ৴߸Λ‫؍‬ଌͰ͖ͨɻ

H → bb̄ ่յࣄ৅Λ 5.4σ Ͱॳ‫؍‬ଌͱ͍͏݁ՌΛICHEP2018 Ͱൃද͕ͨ͠, ͦ͜ʹࢸΔ·Ͱʹ, ࣮ࡍͷ‫ݱ‬৔Ͱ͸ϥΠόϧ࣮‫͋Ͱݧ‬Δ CMS ͱͷൃ‫ݟ‬ΛΊ͙Δ
༷ʑͳ΍ΓऔΓʢࠞཚ?ʣ͕͋ͬͨɻ಺෦৘ใ΋গ͠‫ؚ‬·ΕΔ͕, ‫ݱ‬৔ʹ͍ͨਓؒͷཱ৔͔Β, গ͚ͩ͠৮Ε͞

414

ਤ 8: V H, H → bb̄ ੜ੒่յաఔͷ୳ࡧʹ͓͚Δ

log10 (S/B) ෼෍ɻԼͷύωϧʹ͸σʔλͱ༧૝͞ΕΔ
എ‫ࣄܠ‬৅ͷ͔ࠩΒ‫͞ࢉܭ‬ΕΔ༗ҙ౓͕ࣔ͞Ε͍ͯΔɻ࣮ઢ͸, ώοάεཻࢠͷ৴߸Λ μ = 1.16 ʹ‫֨ن‬Խͨ͠෼෍
Ͱ͋Δɻ
͍͖͍ͤͯͨͩͨɻ
౰ॳ, ղੳνʔϜ͸ 36 fb−1 ͷ݁Ռ͔Β 80 fb−1 ͰಘΒΕΔ‫౓ײ‬Λ༧૝͠, σʔλΛ૿΍͚ͩ͢Ͱ͸ 5σ ʹ౸ୡ͠ͳ͍ͱ‫ࠐݟ‬ΜͰ͍ͨɻ‫ܥ‬౷‫ࠩޡ‬Λ‫ݮ‬Β͢΂༷͘ʑͳղ
ੳͷվળʹऔΓ૊ΜͰ͓Γ, 5σ Λ໨ࢦͯ͠ 2018 ೥ळͷࠃࡍձٞΛλʔήοτʹ͍ͯͨ͠ɻ6 ݄த०ʹ೔ຊͰ։࠵͞Εͨ ATLAS Overview Week Ͱ, ‫ݱ‬ঢ়ͷ༧૝‫౓ײ‬͸5σ ʹগ͠ಧ͔ͳ͍͕, ͍͔ͭ͘ͷ‫౓ײ‬վળख๏ΛಋೖதͰ͋Γ, ൃ‫ॱ͚ͯ޲ʹݟ‬ௐʹղੳ͕ਐΜͰ͍Δͱใࠂͨ͠ɻ͔͠͠, ͦͷ௚‫ ޙ‬CMS ͕ ICHEP2018 Ͱൃ‫ݟ‬ͷใࠂΛ͢ΔՄೳੑ͕͋Δͱ͍͏ӟ͕෣͍ࠐΜͰ͖ͨɻtt̄Hੜ੒աఔͷൃ‫ Ͱݟ‬CMS ʹઌΛӽ͞Ε͍ͯΔ ATLAS ट೴෦͸ 2 ࿈ഊ͸ආ͚͍ͨͱ, ղੳνʔϜʹ݁ՌΛ‫͙ٸ‬Α͏ʹଧ਍͖ͯͨ͠ɻ͔͠͠, ͢Ͱʹ 6 ݄΋Լ०ʹֻ͔͍ࠩͬͯ͠Δɻ7 ݄ 4 ೔͔Β࢝·Δ ICHEP2018 ʹ޲͚ͯ,ATLAS ಺෦ͷঝೝͳͲͷ࣌ؒ΋‫ؚ‬ΊΔͱ΄΅ෆՄೳͳཁ‫ͨͬ͋Ͱٻ‬ɻͦͷͨΊ ATLAS εϙʔΫεύʔιϯͰ
͋Δ Karl Jacob ͸, 7 ݄Լ०ʹ‫ڞ‬ಉηϛφʔͰൃද͢Δ
ͱ͍͏ఏҊΛ͕ͨ͠, CMS ͸ͦͷఏҊʹ৐Βͳ͔ͬͨɻ
ͦͷ࢟੎͔Β CMS ͸ ICHEP2018 ʹ޲͚ͯ४උ͕ਐΜ
Ͱ͍ΔՄೳੑ͕͋Γ, ATLAS ΋४උΛͤ͟ΔΛಘͳ͍ঢ়‫ͨͬͳʹگ‬ɻ࣌ؒతʹશͯͷ‫౓ײ‬վળख๏ΛೖΕΔ͜
ͱ͸ෆՄೳ͕ͩ, 5σ ʹಧ͔ͳ͍ϦεΫΛऔΓͭͭ΋, ग़དྷΔ‫ݶ‬Γͷվળ͸ಋೖ͠ ICHEP2018 ʹ޲͚ͯ࢑ఆ݁Ռ
Λ·ͱΊΔํ޲ʹܾ·ͬͨɻ͜ͷ࣌఺Ͱ ICHEP2018 ·Ͱ 2 िؒΛ੾͍ͬͯͨɻͦͷؒʹ΋΄΅ຖ೔εϙʔΫਤ 9: bb ෆม࣭ྔ෼෍ɻԼͷύωϧʹ͸σʔλ͔Βഎ‫ܠ‬ࣄ৅Λࠩ͠Ҿ͍ͨ෼෍ͱ༧૝͞ΕΔώοάεཻࢠͷ৴߸ࣄ৅ͷ෼෍͕ࣔ͞Ε͍ͯΔɻ
εύʔιϯ, ෺ཧάϧʔϓͷίʔσΟωʔλ͔Βܾ·ͬͯ 18:00 ʹটू͕͔͔Γ, CMS ͷঢ়‫گ‬΍ ATLAS ಺ͰͷঝೝͷਐΊํͳͲΛٞ࿦ͨ͠ɻCMS ͷӟ΋೔ຖʹೋసࡾస͢Δͳ͔, σʔλΛΞϯϒϥΠϯυͰ͖ͨͷ͸ 7
݄ 1 ೔ͩͬͨɻ͜ͷ࣌఺Ͱ ICHEP2018 ͷύϥϨϧηο
γϣϯʹ͸ؒʹ߹Θͣ, 7 ݄ 9 ೔ͷϓϨφϦʔηογϣϯͰ݁ՌΛॳެද͢Δ͜ͱʹͳΓ, ձٞதʹ݁Ռ͕Ξοϓσʔτ͞ΕΔͱ͍͏υλόλܶͩͬͨɻCMS ͸ͱ͍͏ͱ, ݁‫ ہ‬ICHEP2018 ʹ͸ؒʹ߹Θͳ͔ͬͨɻͦͷ‫ޙ‬,ATLAS/CMS Ͱ 8 ݄ 28 ೔ʹ‫ڞ‬ಉηϛφʔΛͯ͠࿦จΛಉ೔ʹ౤ߘ͢Δͱ͍͏ํ਑Ͱ߹ҙ͕ಘΒΕ, ϓϨεϦϦʔε΍࿦จͷ४උΛਐΊͨɻ౤ߘͨ͠࿦จ͸໿ 1 िؒͰΞΫηϓτ͞ΕΔͱ͍͏͓·͚෇͖Ͱ, H → bb̄ ่յͷॳ‫؍‬ଌͷࠞཚ͸ऩଋͨ͠ɻ

H → bb̄ ่յͷൃ‫ޙݟ‬, Run 2 શσʔλΛ༻͍ͯ౷‫ܭ‬‫ࠩޡ‬Λ‫ݮ‬Βͭͭ͠, എ‫ࣄܠ‬৅ͷ‫ܥ‬౷‫ࠩޡ‬ͷ࡟‫ݮ‬ख๏ͷվྑ΍‫ػ‬ցֶश΁ͷ৽͍͠ม਺ͷಋೖʹΑΓ, ਫ਼౓ͷ޲্+0.18
Λ໨ࢦͨ͠ [11]ɻ‫؍‬ଌͨ͠৴߸‫౓ڧ‬͸, μbb
V H = 1.02−0.17

ͱ໿ 17%ͷਫ਼౓Ͱඪ४໛‫ͱܕ‬Ұக͍ͯ͠Δ͜ͱΛ֬ೝͨ͠ʢਤ 10ʣɻ·ͨ, ‫؍‬ଌ͞Εͨ༗ҙ౓͸ 6.7σ ʹ޲্͠,

W H, ZH ͷੜ੒աఔʹ෼͚ͨ৔߹΋, ͦΕͧΕ 4.0σ,
5.3σ ͱ༗ҙͳ৴߸Λ Run 2 Ͱ‫؍‬ଌ͢Δ͜ͱʹ੒ޭͨ͠ɻ
V H, H → bb̄ ৴߸͕༗ҙʹ‫؍‬ଌ͞Εͨ͜ͱͰ, ୳ࡧ͔Β

515ਫ਼ີଌఆͷ࣌୅΁ͱೖͬͨɻ͋ͱͷষͰ, ඍ෼அ໘ੵଌ

μμ ෆม࣭ྔͷ෼ղೳΛ޲্ͤ͞Δ͜ͱͰ͋Δʢਤ 11ʣɻఆͷ݁Ռ΋঺հ͢Δɻ

௿ΤωϧΪʔͷޫࢠΛύΠϧΞοϓʹ༝དྷ͢Δޫࢠͱ෼཭͢Δख๏ͷߏங͕ෆՄܽͰ͋ͬͨɻATLAS ࣮‫Ͱݧ‬͸, Run 2 ͷ͢΂ͯͷσʔλΛ༻͍ͯ, ༗ҙ౓ 2.0σ, ৴߸‫ ౓ڧ‬μ = 1.2 ± 0.6 Λಘͨʢਤ 12ʣ [12]ɻCMS ࣮‫Ͱݧ‬͸, ༗ҙ౓ 3.0σ, ৴߸‫౓ڧ‬+0.15

μ = 1.19+0.40−0.39 (stat.)−0.14 (syst.) Λಘͨʢਤ 13ʣ [13]ɻ
ATLAS ࣮‫ ͱݧ‬CMS ࣮‫ݧ‬ͷ‫౓ײ‬ͷҧ͍͸, ιϨϊΠυ࣓৔ͷҧ͍ʢ2.0 T ͱ 3.8 TʣʹΑΔϛϡʔΦϯͷӡಈྔ෼ղೳͷҧ͍Ͱઆ໌Ͱ͖ΔɻRun 2 ։࢝౰ॳ, H → μμ ่յͷஹީΛಘΒΕΔ͜ͱ͸༧૝͍ͯ͠ͳ͔͕ͬͨ, ղੳख๏ͷվྑΛੵΈॏͶ, ͜͜·Ͱ౸ୡͰ͖ͨ͜ͱ͸, ‫ײ‬֒ਂ͍ɻRun 3 ʹ͓͍ͯ, ATLAS ࣮‫ ͱݧ‬CMS ࣮‫ݧ‬ͷ݁Ռͷ౷߹ʹΑΓ, 5σ Λ௒͑Δ‫౓ײ‬Λ࣮‫͖Ͱݱ‬ΔՄೳੑਤ 10: ‫؍‬ଌ͞Εͨ৴߸‫౓ڧ‬ɻW H, ZH ৴߸Λ̎ύϥ͕͋Γ, ৴߸ͷൃ‫͕ݟ‬໨લʹഭ͍ͬͯΔɻϝʔλͰϑΟοτͨ݁͠Ռͱ, V H(W H + ZH) ͷ̍ύϥϝʔλͰϑΟοτͨ݁͠ՌΛࣔ͢ɻ

3.3ϛϡʔΦϯ౬઒݁߹ͷஹީATLAS ࣮‫͍͓ͯʹݧ‬, ࠷΋ߴ͍‫Ͱ౓ײ‬ώοάεཻࢠͱͷ݁߹Λ‫͖Ͱূݕ‬Δୈೋੈ୅ϑΣϧϛΦϯ͸, ϛϡʔΦϯͰ͋Δɻୈೋੈ୅ϑΣϧϛΦϯͷ͏ͪ, ࠷΋࣭ྔ͕େ͖
͘ώοάεཻࢠͱͷ݁߹͕‫͑ߟͱ͍ڧ‬ΒΕΔͷ͸νϟʔϜΫΥʔΫͰ͋Δ͕, ཅࢠɾཅࢠিಥΛ༻͍Δ ATLAS࣮‫Ͱݧ‬͸, ‫͍ڧ‬૬‫ʹ༻࡞ޓ‬༝དྷ͢Δ๲େͳഎ‫ࣄܠ‬৅ͷӨ‫Ͱڹ‬, H → cc̄ ่յͷൃ‫ݟ‬͸‫ۃ‬Ίͯ೉͍͠ɻϛϡʔΦϯ͸, ࣭ྔ͕খ͘͞ώοάεཻࢠͱͷ݁߹͸૬Ԡʹऑ͍ͱߟ͑ΒΕΔ͕, H → μμ ่յͷ୳ࡧʹ͓͍ͯ͸‫͍ڧ‬૬‫ޓ‬࡞༻ʹ༝དྷ͢Δഎ‫ࣄܠ‬৅͸ແࢹͰ͖Δɻਤ 11: H → μμ ่յͷγϛϡϨʔγϣϯʹ͓͚Δ μμ ෆม࣭ྔͷ෼෍ɻऴঢ়ଶͷޫࢠΛ‫ݕ‬ग़Ͱ͖Δࣄ৅ʢશମͷ5%΄Ͳʣʹରͯ͠, ऴঢ়ଶͷޫࢠΛ༻͍ͨิਖ਼લʢനൈ
͖ʣ, ิਖ਼‫ޙ‬ʢࣼઢʣͷ෼෍Λࣔ͢ɻH → μμ ่յͷ୳ࡧʹ͓͚Δ࠷େͷোน͸, ಉ͡ऴঢ়ଶΛ࣋ͭ Z → μμ ่յͰ͋Δɻώοάεཻࢠͱ Z Ϙιϯͷ࣭ྔʹ͸ 34 GeV ΄Ͳͷҧ͍͕͋Γ, Z Ϙιϯͷࣗવ෯͸ 2.5 GeV ͱ૬ରతʹখ͍͕͞, ͦΕΒΛ྇կ͢Δ

Z → μμ ่յ͕ൃੜ͢Δɻඪ४໛‫͚͓ʹܕ‬Δ H → μμ่յͷ෼‫ذ‬ൺ͸ 2 × 10−4 ͱখ͍͕͞, Run 2 Ͱऔಘͨ͠

σʔλͷதͰ, 1500 ࣄ৅΄Ͳੜ੒͞Εͨͱߟ͑ΒΕΔɻ
ऴঢ়ଶ͕࣮‫ݧ‬తʹΫϦʔϯͰ, ͜Ε͚ͩͷ৴߸͕ੜ੒͞
Ε͍ͯΕ͹‫؍‬ଌͰ͖ͦ͏ͳ‫ؾ‬΋͢Δ͕, Z → μμ ่յ͕‫؍‬ଌΛ೉͍ͯ͘͠͠ΔͷͰ͋Δɻ

Run 2 ʹ͓͍ͯ͸, ͋ΒΏΔղੳख๏ͷվྑΛੵΈॏͶΔ͜ͱͰ, Z → μμ ่յͱͷ෼཭Λ޲্͖ͤͯͨ͞ɻ
ಛʹ, Run 2 ͷҰ෦ͷσʔλʢ36 fb−1 ʣΛ༻͍ͨղੳΛऴ͑ͨࠒ͔Β, ղੳνʔϜΛେ෯ʹ‫ڧ‬Խ͠, Run 2 ͷ͢΂ͯͷσʔλʢ139 fb−1 ʣΛ༻͍ͨղੳ·Ͱͷؒʹ, ղੳख๏͚ͩͰ 25%ͷ‫্޲౓ײ‬Λ࣮‫ͨ͠ݱ‬ɻվྑͷҰྫ͸,ऴঢ়ଶͰ์ग़͞ΕΔޫࢠͷΤωϧΪʔΛՃຯ͢Δ͜ͱͰਤ 12: ATLAS ࣮‫ݧ‬ͷ H → μμ ่յͷ୳ࡧʹ͓͚Δ μμෆม࣭ྔͷϑΟοτ݁ՌɻσʔλʢΤϥʔόʔ෇͖υοτʣ, શ੒෼ͷ࿨ʢ࣮ઢʣ, എ‫ࣄܠ‬৅੒෼ʢ఺ઢʣΛࣔ͢ɻ

616

ਤ 13: CMS ࣮‫ݧ‬ͷ H → μμ ่յͷ୳ࡧʹ͓͚Δ μμෆม࣭ྔͷϑΟοτ݁ՌɻσʔλʢΤϥʔόʔ෇͖υοτʣ, શ੒෼ͷ࿨ʢ࣮ઢʣ, എ‫ࣄܠ‬৅੒෼ʢ఺ઢʣΛࣔ͢ɻώοάεཻࢠͷੑ࣭ͷਫ਼ີଌఆ4

125 GeV ͷώοάεཻࢠ͸, ੑ࣭ͷਫ਼ີଌఆͷ‫Ͱ఺؍‬͸ඇৗʹྑ͍࣭ྔΛ͓࣋ͬͯΓ, ༷ʑͳੜ੒աఔͱ่յ

ਤ 14: ͦΕͧΕͷੜ੒աఔɾ่յʹରͯ͠ଌఆ͞Εͨஅ໘ੵͱ่յ෼‫ذ‬ൺͷੵΛඪ४໛‫ܕ‬ͷ༧૝஋Ͱ‫֨ن‬Խͨ͠஋ɻͰ৴߸͕‫؍‬ଌՄೳͰ͋Δɻओཁͳੜ੒աఔ (ggF, VBF,W H, ZH, tt̄H) ͱ่յ (γγ, ZZ ∗ , W W ∗ , τ τ , bb̄, μμ)͸, ඪ४໛‫ܕ‬ͷཻࢠͷΈͷଘࡏΛԾఆ͠, ggF ੜ੒աఔͷ૊Έ߹ΘͤʹΑΓੑ࣭Λৄࡉʹௐ΂͍ͯΔɻώοάε΍ H → γγ ่յͰ‫ݱ‬ΕΔϧʔϓͷ‫د‬༩͸ κi ͷ݁߹ͱཻ͠ࢠͷੑ࣭Λਫ਼ີʹௐ΂ΔͨΊʹ͸ͦΕͧΕͷղੳͷ‫ײ‬ͯѻ͍ͬͯΔɻκZ , κW , κt ͸, 10%ҎԼͷਫ਼౓, κb , κτ౓Λ࠷େԽ͢Δͱͱ΋ʹ, ༷ʑͳνϟϯωϧΛ౷‫ܭ‬తʹ

͸ 15%ఔ౓, κμ Ͱ΋ 30%ఔ౓ͷਫ਼౓Ͱඪ४໛‫ͱܕ‬Α͘౷߹͢Δ͜ͱ͕ॏཁͰ͋Δɻ

Ұக͍ͯ͠ΔɻτοϓΫΥʔΫͱϛϡʔΦϯͰ 3 ܻ΋ҧRun 2 શ σ ʔ λ Λ ࢖ͬͨ ղ ੳ ͕ ΄ ΅ ग़ ଗ ͍ ͭ ͭ͏݁߹ͷ‫͞ڧ‬Λ౬઒݁߹Ͱද‫͖Ͱݱ‬Δͱ͍͏ͷ͸, ඪ४͋Γ, ‫ࡏݱ‬ར༻Ͱ͖Δ݁ՌΛ౷߹͠৴߸‫౓ڧ‬ͷଌఆ໛‫ܕ‬ͷ੒ޭΛҙຯ͍ͯ͠Δ͕, ͋Δҙຯ‫Ͱ͖ڻ‬΋͋ΔɻΛ ߦͬͨ ɻ৴ ߸ ‫ ౓ ڧ‬͸ μ=1.06 ± 0.04(stat.) ±+0.05
0.03(exp.)−0.04 (sig. th.) ± 0.02(bkg. th.) ͱ, ໿ 7%ͷਫ਼ώοάεཻࢠ͸ඪ४໛‫Ͱܕ‬།Ұੈ୅ؒͰ݁߹ͷ‫͞ڧ‬͕ҧ͏ಛघͳૉཻࢠͰ͋Γ, ͜ͷ͕ࠩૉཻࢠͷ࣭ྔͷҧ౓Ͱඪ४໛‫͍ྑͱܕ‬ҰகΛಘ͍ͯΔ [14]ɻਤ 14 ͸, ଌ͍ɾੈ୅Λ૑͍ͬͯΔͱ͍͏͜ͱ΋໌Β͔ʹͨ͜͠ͱ͸,ఆՄೳͳੜ੒աఔͱ่յͷ૊Έ߹ΘͤͰ, 16 ύϥϝʔλRun 2 ͷώοάε෺ཧʹ͓͚Δେ͖ͳ੒Ռͱ‫͑ݴ‬ΔɻΛಉ࣌ϑΟοτͯ͠ಘͨੜ੒அ໘ੵͱ่յ෼‫ذ‬ൺͷੵΛඪ४໛‫֨نʹܕ‬Խͨ͠ଌఆ݁ՌͰ͋Δɻ‫ࡏݱ‬ͷଌఆਫ਼౓Ͱ, Α͘ඪ४໛‫ܕ‬Λ‫ه‬ड़͍ͯ͠Δ͜ͱ͕֬ೝ͞Εͨɻ

4.2

ώοάεཻࢠͷඍ෼அ໘ੵଌఆ

Run 2 ͷߴ౷‫ܭ‬σʔλͰ, ඍ෼அ໘ੵଌఆͳͲώοά

4.1

ώοάεཻࢠͱඪ४໛‫ࢠཻܕ‬ͷ݁߹ώοάεཻࢠͱΫΥʔΫɾϨϓτϯ, ήʔδϘιϯͷ
݁߹ఆ਺Λඪ४໛‫ܕ‬ͷ༧૝஋Ͱ‫֨ن‬Խͨ͠ύϥϝʔλ κεཻࢠͷӡಈֶతੑ࣭͔Β৽෺ཧΛ୳ࡧ͢Δଌఆ͕Մೳ
ʹͳ͖͍ͬͯͯΔɻಛʹऴঢ়ଶ͕ΫϦʔϯͳ γγ ΍ ZZ
่յͰώοάεཻࢠͷੜ੒աఔ (pp → H + X) ͷඍ෼அ໘ੵ͕ଌఆ͞Ε͍ͯΔ [15]ɻਤ 16 ͸, ώοάεཻࢠͰද͢͜ͱʹΑΓ, ༷ʑͳੜ੒ɾ่յաఔʹؔ༩͢Δ૬ͷԣӡಈྔͷඍ෼அ໘ੵଌఆ݁ՌΛ͍ࣔͯ͠ΔɻggF ͕‫༻࡞ޓ‬Λ౷Ұతʹѻ͏͜ͱ͕ग़དྷΔɻਤ 15 ͸ t, Z, W ,ओཁͳੜ੒աఔͰ͋Γ, ϧʔϓʹ৽ཻࢠ͕‫د‬༩͢Δ৔߹

b, τ , μ ͱώοάεཻࢠͷ݁߹ύϥϝʔλΛ κi=t,Z,W,b,τ,μͱͯ͠ଌఆ͠, ݁߹‫ͨ͠ࢉ׵ʹ౓ڧ‬΋ͷΛͦΕͧΕͷૉ΍౬઒݁߹͕ඪ४໛‫͔ܕ‬ΒͣΕΔ৔߹, ඍ෼அ໘ੵଌఆ
͸৽෺ཧʹߴ͍‫͕͋౓ײ‬Δɻ༗ҙͳζϨ͸‫؍‬ଌ͞Εཻ͍ͯࢠͷ࣭ྔͷؔ਺ͱͯ͠ද͍ͯ͠Δ [14]ɻ͜ͷଌఆͰͳ͍͕, ߴӡಈྔྖҬ (pHT > 200 GeV) Ͱͷஅ໘ੵଌఆ

717

ਤ 16: ώοάεཻࢠͷԣӡಈྔͷඍ෼அ໘ੵɻώετਤ 15: ݁߹ͷ‫͞ڧ‬ʢϑΣϧϛΦϯʹରͯ͠͸ κF mF /v,√Ϙιϯʹରͯ͠͸ κV mV /v) Λૉཻࢠͷ࣭ྔͷؔ਺ͱάϥϜ͸ NNLOPS ggF ͷ༧૝஋Λ N3 LO ͷ༧૝஋ʹεͯ͠දͨ͠΋ͷɻ఺ઢ͸ඪ४໛‫ܕ‬ͷ༧૝௚ઢΛࣔͯ͠έʔϧͨ͠΋ͷʹଞͷώοάεཻࢠੜ੒աఔΛ଍͠߹Θ

͍Δɻ

ͤͨ΋ͷɻ

ʹ͓͍ͯ΋, ‫ ࠩޡ‬15%ఔ౓ͷਫ਼౓·Ͱ౸ୡ͍ͯ͠Δɻ
·ͨ, Simpliﬁed Template Cross Section (STXS) [16]ͱͯ͠৽෺ཧʹ‫ྖ͍ߴ͕౓ײ‬ҬΛఆٛ͠, ֤ྖҬͰஅ໘ੵΛਫ਼ີଌఆ͢Δ͜ͱͰ, ৽෺ཧͷஹީΛ‫؍‬ଌ͠Α͏ͱࢼΈ͍ͯΔɻSTXS ͷ֤ྖҬ͸, ཧ࿦తͳෆఆੑΛ཈͑ͭͭ, ৽෺ཧʹ‫͍ߴ͕౓ײ‬ώοάεཻࢠͷੜ੒աఔͷӡಈֶత৘ใͰఆٛ͞Ε͓ͯΓ่յʹ͸ґΒͳ͍ɻ༷ʑͳ
่յΛ༻͍ͯ౷Ұతͳଌఆ͕ՄೳͰ͋Γ, ࣮‫ݧ‬తͳ‫౓ײ‬ΛଛͶΔ͜ͱͳ͘ଌఆਫ਼౓ΛߴΊΔ͜ͱ͕ग़དྷΔɻਤ 17
͸, γγ, ZZ, bb̄ ่յΛ༻͍ͯଌఆͨ͠ STXS ΧςΰϦʔͷ৴߸‫౓ڧ‬Λද͍ͯ͠Δ [17]ɻ༗ҙͳඪ४໛‫͔ܕ‬ΒͷζϨ͸‫؍‬ଌ͞Ε͍ͯͳ͍͕, ౷‫ࢧ͕ࠩޡܭ‬഑తͰ͋Γ, σʔλྔΛ૿΍͠, ଞͷੜ੒աఔ΍่յΛղੳ͢Δ͜ͱͰ৽෺ཧ΁ͷ‫ظ্͕޲౓ײ‬଴Ͱ͖Δɻ·ͨ, STXS ͷଌఆΛ‫ʹج‬༗ޮ৔ཧ࿦ͷύϥϝʔλʢWilson ܎਺ʣʹ࣮‫ݧ‬తͳ੍‫ݶ‬΋༩͍͑ͯΔɻ[17] ʹ·ͱΊΒΕ͍ͯΔͷͰ‫ڵ‬ຯ͕͋Δಡऀ͸ͦͪΒΛࢀߟʹ͍͖͍ͯͨͩͨ͠ɻ
͞Βʹ৽෺ཧʹ‫ྖ͍ߴ͕౓ײ‬Ҭͷଌఆʹ΋औΓ૊ΜͰ͓Γ, Ұ͚ͭͩ঺հ͢ΔɻΑΓߴ͍ԣӡಈྔΛ࣋ͭώοάεཻࢠͷੑ࣭Λଌఆ͢ΔͨΊʹ, ่յ෼‫ذ‬ൺ͕ߴ͍H → bb̄ ่յࣄ৅͕ॏཁʹͳΔɻώοάεཻࢠͷ࣭ྔʹରͯ͠ԣӡಈྔ͕ߴ͍৔߹, ώοάεཻࢠͷ่յͰੜ੒

͞ΕΔ b δΣοτ͸ۙ઀͢ΔͨΊ, ೋͭͷ b δΣοτΛબ୒͢Δैདྷͷํ๏Ͱ͸ଌఆ͕ࠔ೉ʹͳΔɻͦͷͨΊ, େ൒‫ܘ‬δΣοτ (R = 1.0) ͷதʹೋͭͷ b λά͞ΕͨαϒδΣοτ͕͍ΔτϙϩδʔΛબͿ͜ͱͰ, എ‫ࣄܠ‬৅Λ཈͑ͭͭߴӡಈྔώοάεཻࢠͷଌఆ͕ՄೳͰ͋Δɻਤ 17: H → γγ, H → ZZ, H → bb̄ ่յΛ༻͍ͨղੳʹ͓͚Δ, ώοάεཻࢠੜ੒աఔ͝ͱͷ STXS ΧςΰϦʔͰଌఆ͞Εͨ৴߸‫౓ڧ‬ɻඪ४໛‫ܕ‬ΛԾఆͨ͠ࡍͷ‫ݕ‬ఆʹର͢ΔҰக౓͸ 91%ɻ818

ਤ 18 ͸, pH
T > 1 TeV ʹ͓͚Δେ൒‫ܘ‬δΣοτͷ࣭ྔ
෼෍Ͱ͋Δɻԣӡಈྔ͕ 1 TeV Ҏ্ͷྖҬͰଌఆ͞Εͨաఔͷஅ໘ੵͷ 1000 ෼ͷ 1 ҎԼͱখ͘͞, ͦͷ୳ࡧ͸ͱͯ΋௅ઓతͰ͋Δɻ

அ໘ੵ͸, 3.4 ± 3.9(stat.) ± 1.0(syst.) ± 0.8(theory) fbͰ‫ࠩޡ‬͸·ͩେ͖͍͕, ৴߸ͷ౷‫ࢧ͕ࠩޡܭ‬഑తͰ͋Δ [18]ɻ

(a)(b)

ਤ 19: ώοάεཻࢠରੜ੒աఔͷϑΝΠϯϚϯਤɻRun 2 ͷ 27.5–36.1 fb−1 ͷσʔλΛ༻͍ͯߦΘΕͨώοάεཻࢠରੜ੒աఔͷ୳ࡧͰ͸, 95%৴པ౓ͷ্‫ݶ‬஋͕, ਤ 20 ʹࣔ͢௨ΓʹಘΒΕ͍ͯΔ [19]ɻ౷߹͢Δͱ, ඪ४໛‫ܕ‬ͷ໿ 10 ഒͷੜ੒அ໘ੵ·Ͱ‫غ‬٫͞ΕΔɻ

2027 ೥։࢝༧ఆͷߴً౓ LHC [20] Ͱ͸, ੵ෼ϧϛϊγςΟ3000–4000 fb−1 ͷσʔλΛऔಘ͢Δɻඪ४໛‫ܕ‬ΛԾఆͨ͠ͱ͖ʹ, 3.0σ ͷ༗ҙ౓Ͱώοάεཻࢠରੜ੒աఔͷ৴߸ͷূ‫ڌ‬ΛಘΒΕΔͱ͍͏‫ੵݟ‬΋Γ͕͋Δ [21]ɻ͜ͷ‫ੵݟ‬΋Γ͸, ࣗ‫߹݁ݾ‬ͷඪ४໛‫ʹܕ‬ର͢Δ−1ൺ κλ = 1.0+0.7−0.6 ʹ૬౰͢Δɻͨͩ͠, ͜ΕΒ͸ 36 fbͷղੳΛ֎ૠͨ͠΋ͷͰ, ͦͷ‫ޙ‬ͷख๏վྑΛՃຯͨ͠΋ͷͰ͸ͳ͍ɻ͢Ͱʹ, 139 fb−1 ͷσʔλΛ༻͍ͨղੳ
Ͱ‫্޲౓ײ‬Λ࣮‫͓ͯ͠ݱ‬Γ [22, 23], ߴً౓ LHC Ͱ͸,ΑΓߴ͍‫Ͱ౓ײ‬ղੳΛߦ͑Δɻਤ 18: H → bb̄ ่յΛ༻͍ͨ, ԣӡಈྔ͕ 1 TeV Ҏ্Λ࣋ͭେ൒‫ܘ‬δΣοτͷ࣭ྔ෼෍ɻ

ओཁͳੜ੒ɾ่յϞʔυ͕શͯ Run 2 Ͱ‫؍‬ଌ͞Εͨ͜ͱͰ, ώοάεཻࢠͷਫ਼ີଌఆ͸ΑΓ৽෺ཧʹ‫͕౓ײ‬ߴ͍Ґ૬ۭؒͷଌఆͳͲʹਐΜͰ͍ΔɻͦͷΑ͏ͳྖҬͰ͸౷‫ࢧͩ·͕ࠩޡܭ‬഑తͰ͋ΔͨΊ, ࠓ‫ʹߋޙ‬σʔλ͕૿͑Δ͜ͱͰ, ਫ਼౓ͷ޲্͕‫ظ‬଴Ͱ͖Δɻώοάεཻࢠͷਫ਼ີଌఆ͸͜Ε͔Β͕ຊ൪Ͱ͋Δɻਤ 20: ώοάεཻࢠରੜ੒աఔͷ୳ࡧ݁Ռͷ·ͱΊɻ5ώοάεཻࢠରੜ੒ͷ୳ࡧώοάεཻࢠͷࣗ‫߹݁ݾ‬Λଌఆ͢Δ͜ͱ͕Ͱ͖Ε͹,6ඪ४໛‫ܕ‬Λ௒͑Δώοάε୳ࡧϙςϯγϟϧͷ‫ܗ‬ঢ়ͷ৘ใ͕ಘΒΕ, ώοάε‫ߏػ‬ͷ௚௒ରশੑͳͲͷඪ४໛‫ܕ‬Λ௒͑Δ෺ཧͰ͸, Two Higgs

઀తͳ‫ূݕ‬Λߦ͑Δɻࣗ‫߹݁ݾ‬ͷଌఆ͸, ώοάεཻࢠ

Doublet Model (2HDM) ʹ୅ද͞ΕΔΑ͏ͳώοάεη

ରੜ੒աఔΛ༻͍ͯߦ͏ɻࢧ഑తͳաఔ͸, ਤ 19 ʹࣔΫλʔͷ֦ு͕༧‫͞ݴ‬Ε͓ͯΓ, ώοάεཻࢠ͸Ұͭͩ͢ೋͭͰ͋Γ, ࣗ‫͕߹݁ݾ‬ଘࡏ͢Δաఔʢࠨʣͱଘࡏ͠

͚Ͱ͸ͳ͘, ͍͔ͭ͘ͷώοάεཻࢠ͕ଘࡏ͢ΔՄೳੑ

ͳ͍աఔʢӈʣ͕‫ׯ‬ব͢Δɻඪ४໛‫͚͓ʹܕ‬Δώοάε

͕͋Δɻ“࣍ͷ” ώοάεཻࢠ͕‫؍‬ଌ͞ΕΕ͹, ৽෺ཧͷཻࢠରੜ੒աఔͷஅ໘ੵ͸, ୯Ұͷώοάεཻࢠͷੜ੒ํ޲ੑΛܾΊΔେ͖ͳϚΠϧετʔϯʹͳΔɻATLAS

919࣮‫Ͱݧ‬΋༷ʑͳ୳ࡧ͕ߦΘΕ͓ͯΓ [3], ࠷৽ͷ݁ՌΛϐοΫΞοϓͯ͠঺հ͍ͨ͠ͱࢥ͏ɻ࠷ খ ௒ ର শ ඪ ४ ໛ ‫ ܕ‬Λ ֦ ு ͠ ͨ Next-to-Minimal

Supersymmetric Standard Model (NMSSM) Ͱ ͸,
125 GeV ΑΓ͍ܰώοάεཻࢠͷଘࡏ΋༧‫͞ݴ‬Ε͓ͯΓ, LHC ࣮‫͕ࡧ୳Ͱݧ‬ՄೳͰ͋Δɻ͜ͷղੳͰ͸, ൃ‫͞ݟ‬Εͨ 125 GeV ͷώοάεཻࢠ͕͍ٖܰεΧϥʔͷώοάεཻࢠରʹ่յ͠, ͞ΒʹϛϡʔΦϯରͱϘτϜΫΥʔΫରʹ่յ͢Δऴঢ়ଶ (H → aa → bbμμ) Λ୳ࡧ͍ͯ͠ΔɻҰํͷώοάεཻࢠ͸, ่յ෼‫ذ‬ൺ͕ߴ͍ϘτϜΫΥʔΫର΁ͷ่յΛબ୒͠‫ݕ‬ग़ޮ཰Λ্͛Δɻ΋͏Ұํͷώοάεཻࢠ͸, ΫϦʔϯͳϛϡʔΦϯରΛબ୒͢Δ͜ͱͰ‫౓ײ‬ΛߴΊ͍ͯΔɻbb ෆม࣭ྔͷ෼ղೳ͸ѱ͍ͨΊʹ, μμ ෆม࣭ྔͱ஋͕͍ۙ͜ͱΛཁ‫͠ٻ‬, b δΣοτʹิਖ਼Λ͔͚Δ͜ͱͰ࣭ྔ෼ղೳΛ޲্͍ͤͯ͞Δɻओͳࣄ৅બ୒ͱͯ͠ bbμμ ෆม࣭ྔ͕

110 GeV < mμμbb < 140 GeV ͱͳΔ͜ͱΛཁ‫͠ٻ‬, ͞Βʹ௿͍ফࣦԣӡಈྔͷબ୒ʹΑΓτοϓΫΥʔΫ༝དྷͷഎ‫ࣄܠ‬৅Λ࡟‫͍ͯ͠ݮ‬Δɻ·ͨ, bb ෆม࣭ྔ΍֯౓෼෍ͷ৘ใΛ‫ػ‬ցֶशʹೖΕ, എ‫ࣄܠ‬৅ͱͷ෼཭ੑೳΛ޲্͍ͤͯ͞Δɻਤ 21 ͸, μμ ෆม࣭ྔ෼෍Λ͍ࣔͯ͠Δɻ

52 GeV ෇ۙʹഎ‫ࣄܠ‬৅͔Βͷ௒ա͕‫ݟ‬ΒΕΔ͕, ‫ॴہ‬తͳ p ஋͸ 3.3σ Ͱ͋Γ, Look-elsewhere ޮՌΛೖΕΔ
ͱ p ஋͸ 1.7σ Ͱ͋Δʢਤ 21ʣ [24]ɻ͜ͷ௒ա͸৴߸͔ΒདྷΔ΋ͷͳͷ͔, ଞͷ่յϞʔυͰ୳ࡧΛਐΊ͓ͯΓࠓ‫ޙ‬ͷ݁Ռʹ‫ظ‬଴ͯ͠΄͍͠ɻ

7·ͱΊ
Run 2 ʹ͓͚Δ࠷େͷ੒Ռ͸, ୈࡾੈ୅ϑΣϧϛΦϯ

ʢτοϓΫΥʔΫ, ϘτϜΫΥʔΫ, λ΢Ϩϓτϯʣͱώοάεཻࢠͷ౬઒݁߹ͷ‫؍‬ଌͰ͋Δɻ༗ҙ౓͸͍ͣΕ΋ 5σΛ௒͑, ඪ४໛‫͚͓ʹܕ‬Δ࣭ྔ‫ݯى‬ͷඳ૾͕͔֬ΊΒΕͨɻୈೋੈ୅ϑΣϧϛΦϯͷҰͭͰ͋ΔϛϡʔΦϯͱͷ݁߹΋, ATLAS ࣮‫ ͱݧ‬CMS ࣮‫ݧ‬ͷ݁ՌΛ౷߹͢Δͱ
3σ Λ௒͑Δ༗ҙ౓ΛಘΒΕ, ୈࡾੈ୅ಉ༷, ඪ४໛‫ʹܕ‬͓͚Δ࣭ྔ‫ݯى‬ͷඳ૾͕ࣔࠦ͞Ε͍ͯΔɻ
ώοάεཻࢠͷσʔλͷ஝ੵ͸, ඍ෼அ໘ੵͷଌఆʹΑΔ৽෺ཧͷؒ઀୳ࡧΛՄೳʹͨ͠ɻ·ͨ, ඪ४໛‫ܕ‬Λ௒͑Δώοάεཻࢠͷ௚઀୳ࡧʹ͓͍ͯ΋ύϥϝʔλྖҬΛ֦େ͍ͯ͠Δɻώοάεཻࢠͷࣗ‫߹݁ݾ‬ͷଌఆʹΑΔώοάεϙςϯγϟϧͷ‫ূݕ‬΋, ౰ॳ͸ 2027 ೥։࢝༧ఆͷߴً౓ LHC Ͱ΋ࠔ೉ͳ՝୊Ͱ͋Δͱߟ͑ΒΕ͍͕ͯͨ, ਺ʑͷվྑʹΑΓ, ߴً౓ LHC Ͱ༗ҙͳ݁ՌΛಘΒΕΔՄೳੑ͕͋Δɻࠓ‫ޙ‬, LHC, ߴً౓ LHC, ‫ܭ‬ը͞Ε͍ͯΔ ILC, FCC ͳͲͷকདྷ࣮‫͍͓ͯʹݧ‬, ώοάεཻࢠͷแ‫ׅ‬తͳ‫ڀݚ‬Λߦ͏͜ͱͰ, ඪ४໛‫ܕ‬Λ௒͑Δ
෺ཧ΁ͷ଍͕͔Γ͕ಘΒΕ, ૉཻࢠ෺ཧֶͷ৽͍͠஍ฏ

ਤ 21: ৴߸ྖҬͷ μμ ෆม࣭ྔ෼෍ʢ্ਤ, ্ύωϧʣɻԼͷύωϧ͸, ֤ϏϯͰͷ‫؍‬ଌ͞Εͨσʔλ͔Βഎ‫ࣄܠ‬৅ͷ༧૝஋ͰҾ͍ͨ΋ͷΛഎ‫ࣄܠ‬৅ͷ‫ׂͨͬͰࠩޡ‬஋ʢ্ਤ, Լύωϧʣɻ‫؍‬ଌ͞ΕͨϛϡʔΦϯରͷෆม࣭ྔʹ͓͚Δ‫ॴہ‬తͳ p ஋ʢԼਤʣɻ
Λ։͘͜ͱ͕Ͱ͖Δͱ‫ظ‬଴͢Δɻ

ࢀߟจ‫ݙ‬[1] ੨໦խਓ, ߴΤωϧΪʔχϡʔεʮLHC ATLAS࣮‫ݧ‬ͷ࠷৽ঢ়‫گ‬ʯ, 37-1, 30 (2018).

[2] த඿༏, ߴΤωϧΪʔχϡʔεʮLHC ATLAS ࣮‫৽࠷ ݧ‬ͷ෺ཧ݁Ռʯ, 37-1, 37 (2018).

[3] https://twiki.cern.ch/twiki/bin/view/AtlasPublic[4] LHC Higgs Cross Section Working Group,“Handbook of LHC Higgs Cross Sections: 4.
Deciphering the Nature of the Higgs Sector”,
CERN-2017-002-M[hep-ph](2016).

arXiv:1610.07922[5] ATLAS and CMS Collaborations, “Measurements of the Higgs boson production and decay rates and constraints on its couplings from a
combined ATLAS and CMS analysis of the LHC√
pp collision data at s = 7 and 8 TeV”, J. HighEnerg. Phys. 2016, 45 (2016).

1020[6] ATLAS Collaboration, “Observation of Higgs
boson production in association with a top quark[16] LHC Higgs Cross Section Working Group,

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“Handbook of LHC Higgs Cross Sections: 4. Deciphering the Nature of the Higgs Sector”, arXiv:
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[7] ATLAS Collaboration, “CP Properties of Higgs
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combined measurement of Higgs boson pro-and tH Processes Using H → γγ with the ATLAS Detector”, Phys. Rev. Lett. 125, 061802(2020).

duction and decay”, ATLAS-CONF-2020-053(2020).

[8] ATLAS Collaboration, “Measurement of the√properties of Higgs boson production at s =13 TeV in the H → γγ channel using 139 fb−1 ofpp collision data with the ATLAS experiment”,
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[9] ATLAS Collaboration, “Measurement of the
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[12] ATLAS Collaboration, “A search for the dimuon
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[18] ATLAS Collaboration, “Measurements of Higgs
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[20] தଜߒೋ, ງҪହ೭, ߴΤωϧΪʔχϡʔεʮߴً౓ LHC ʹ޲͚ͨ ATLAS ‫ݕ‬ग़‫ث‬ΞοϓάϨʔυʯ, 37-2, 101 (2018).

[21] ATLAS Collaboration, “Measurement prospectsof the pair production and self-coupling of the
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