Precision Higgs physics: a gateway to New Physics Jonas M. Lindert - PowerPoint PPT Presentation

Precision Higgs physics: 
 a gateway to New Physics Jonas M. Lindert SM@LHC 2018 Higgs-session 
 Berlin, 10. April 2018

…finding new physics might 
 Finding the Higgs was “easy”… be very tough. [CMS diphoton Higgs search, arXiv:1407.0558] [Grazzini et. al., 2016] ����� � � � ������������� �� � ������������������������ �� � � ������ � ������ � � �������� � � ������ � ������ �� � � � ������ � ������� � � ������ � ������� �� �� �� �� �� �� �� �� �� ���� ���� ���� ���� �� ���� ���� ��� ���� ���� ���� ���� ���� ���� ���� � � � � ������� Look for BSM effects in small deviations from Bump hunting: little to no theoretical SM predictions: input needed. → Higgs processes natural place to look at → good control on theory necessary! 2 Jonas M. Lindert

“good control” ? Imagine to have new physics at a (heavish) scale Λ NP Λ NP Typical modification to observable direct w.r.t. standard model prediction: bounds δ O ~ Q 2 / Λ NP 2 ~ TeV To gain over direct bounds: I N THE T AIL : SM ~ v.e.v. Q ≳ 500 G E V → I N THE BULK : Q~ M H → few percent ~10-20% [F. Caola, Moriond ’17] 3 Jonas M. Lindert

Outline ∆ TH ~5% ∆ TH ~0.5% New! New! • VBF-H: differential NNLO revised • H-inc: mixed QCD-EW H New! • H-pT: NNLO+N3LL New! • H-pT: t & b NLO mass effects ∆ TH ~5% ∆ TH ~1-2% • VH(+jet) @ NLOPS QCD+EW New! New! • ttH: ttbb background modelling 4 Jonas M. Lindert

Outline ∆ TH ~5% ∆ TH ~0.5% • VBF-H: differential NNLO revised New! New! • H-inc: mixed QCD-EW H New! • H-pT: NNLO+N3LL New! • H-pT: t & b NLO mass effects ∆ TH ~5% ∆ TH ~1-2% • ttH: ttbb background modelling New! • VH(+jet) @ NLOPS QCD+EW New! 5 Jonas M. Lindert

inclusive-H [Anastasiou et al.;2016] σ = 48 . 58 pb +2 . 22 pb (+4 . 56%) 13 TeV: − 3 . 27 pb ( − 6 . 72%) (theory) ± 1 . 56 pb (3 . 20%) (PDF+ α s ) . α S2 48 . 58 pb = 16 . 00 pb (+32 . 9%) (LO, rEFT) + 20 . 84 pb (+42 . 9%) (NLO, rEFT) − 2 . 05 pb ( − 4 . 2%) (( t, b, c ), exact NLO) α S3 + 9 . 56 pb (+19 . 7%) (NNLO, rEFT) [Dawson; 1991 Djouadi, Spira, Zerwas;1991] + 0 . 34 pb (+0 . 2%) (NNLO, 1 /m t ) + 2 . 40 pb (+4 . 9%) (EW, QCD-EW) α S4 (N 3 LO, rEFT) + 1 . 49 pb (+3 . 1%) [Harlander, Kilgore; 2002 [Anastasiou, Melnikov; Anastasiou, Melnikov;2002] Harlander, Kilgore] Obtained through a series expansion around the soft limit α S5 1 − z = 1 − m 2 H / ˆ s [Anastasiou et al] [Anastasiou et al.;2015] • remaining uncertainties are at the ~1%-level (and basically everything becomes relevant): δ (scale) δ (trunc) δ (PDF-TH) δ (EW) δ ( t, b, c ) δ (1 /m t ) +0 . 10 pb ± 0.18 pb ± 0.56 pb ± 0.49 pb ± 0.40 pb ± 0.49 pb − 1 . 15 pb +0 . 21% ± 0 . 37% ± 1 . 16% ± 1% ± 0 . 83% ± 1% − 2 . 37% 6 Jonas M. Lindert

inclusive-H [Anastasiou et al.;2016] σ = 48 . 58 pb +2 . 22 pb (+4 . 56%) 13 TeV: − 3 . 27 pb ( − 6 . 72%) (theory) ± 1 . 56 pb (3 . 20%) (PDF+ α s ) . α S2 48 . 58 pb = 16 . 00 pb (+32 . 9%) (LO, rEFT) + 20 . 84 pb (+42 . 9%) (NLO, rEFT) − 2 . 05 pb ( − 4 . 2%) (( t, b, c ), exact NLO) α S3 + 9 . 56 pb (+19 . 7%) (NNLO, rEFT) [Dawson; 1991 Djouadi, Spira, Zerwas;1991] + 0 . 34 pb (+0 . 2%) (NNLO, 1 /m t ) + 2 . 40 pb (+4 . 9%) (EW, QCD-EW) α S4 (N 3 LO, rEFT) + 1 . 49 pb (+3 . 1%) [Harlander, Kilgore; 2002 [Anastasiou, Melnikov; Anastasiou, Melnikov;2002] Harlander, Kilgore] Obtained through a series exact! expansion around the soft limit α S5 1 − z = 1 − m 2 H / ˆ s [Anastasiou et al] [Anastasiou et al.;2015 
 Mistlberger; 2018 ] • remaining uncertainties are at the ~1%-level (and basically everything becomes relevant): δ (scale) δ (trunc) δ (PDF-TH) δ (EW) δ ( t, b, c ) δ (1 /m t ) +0 . 10 pb ± 0.18 pb ± 0.56 pb ± 0.49 pb ± 0.40 pb ± 0.49 pb − 1 . 15 pb +0 . 21% ± 0 . 37% ± 1 . 16% ± 1% ± 0 . 83% ± 1% − 2 . 37% 7 Jonas M. Lindert

inclusive-H [Anastasiou et al.;2016] σ = 48 . 58 pb +2 . 22 pb (+4 . 56%) 13 TeV: − 3 . 27 pb ( − 6 . 72%) (theory) ± 1 . 56 pb (3 . 20%) (PDF+ α s ) . α S2 48 . 58 pb = 16 . 00 pb (+32 . 9%) (LO, rEFT) + 20 . 84 pb (+42 . 9%) (NLO, rEFT) − 2 . 05 pb ( − 4 . 2%) (( t, b, c ), exact NLO) α S3 + 9 . 56 pb (+19 . 7%) (NNLO, rEFT) [Dawson; 1991 Djouadi, Spira, Zerwas;1991] + 0 . 34 pb (+0 . 2%) (NNLO, 1 /m t ) + 2 . 40 pb (+4 . 9%) (EW, QCD-EW) α S4 (N 3 LO, rEFT) + 1 . 49 pb (+3 . 1%) [Harlander, Kilgore; 2002 [Anastasiou, Melnikov; Anastasiou, Melnikov;2002] Harlander, Kilgore] Obtained through a series exact! expansion around the soft limit α S5 1 − z = 1 − m 2 H / ˆ s [Anastasiou et al] [Anastasiou et al.;2015 
 Mistlberger; 2018 ] • remaining uncertainties are at the ~1%-level (and basically everything becomes relevant): δ (scale) δ (trunc) δ (PDF-TH) δ (EW) δ ( t, b, c ) δ (1 /m t ) +0 . 10 pb ± 0.18 pb ± 0.56 pb ± 0.49 pb ± 0.40 pb ± 0.49 pb − 1 . 15 pb +0 . 21% ± 0 . 37% ± 1 . 16% ± 1% ± 0 . 83% ± 1% − 2 . 37% 8 Jonas M. Lindert

inclusive-H: mixed QCD-EW @ NLO [Bonetti, Melnikov, Tancredi; ‘17+’18 ] g V=W,Z • requires very complicated three-loop virtuals and two-loop reals. q g H • literature result [Anastasiou, Boughezal, Petriello; ’09 ] based on 
 g unphysical limit MV ≫ MH yields 5(±1)% contribution. g • this limit corresponds to a point-like ggH QCD-EW coupling. V ????? • Two-loop reals not yet available, but (improved) soft-gluon 
 q g H approximation known to be quite reliable for inclusive Higgs. g • Only non-universal ingredient required for soft gluon approximaton : 
 three-loop virtuals 
 QCD / EW = 39 . 0 pb . } σ LO σ LO QCD = 20 . 6 pb , QCD / EW = 21 . 7 pb , • Result: σ (N)LO QCD / EW / σ (N)LO = 5 . 3 − 5 . 4% QCD σ NLO σ NLO QCD = 37 . 0 pb , consistent! • Further improvements and updated uncertainty estimate requires computation of the very challenging two-loop reals! 9 Jonas M. Lindert

Higgs-pT / Higgs+jet ~ c t X • Motivation: ? ~ c g ‣ Higgs-pT sensitive probe of New Physics 
 H ~ c g ➜ In particular: disentangle c g vs. c t ‣ Possibility to constrain the charm-Yukawa coupling 
 ����� � � � ������������� [Bishara, Haisch, Monni, Re; ’16] �� � ������������������������ �� � � ������ � ������ � � �������� • When we are inclusive in the radiation recoiling � � ������ � ������ �� � � � ������ � ������� � � ������ � ������� against the Higgs we can measure its pT. [Grazzini et. al., 2016] �� �� • At LO in inclusive-H: pTH = 0 
 �� �� ➜ Consider Higgs+jet production �� �� �� �� �� ���� ���� ���� ���� • Two regimes: �� ���� ���� ��� ���� ���� ���� ���� ���� ���� ���� � � � � ������� + ∞ p T ⌧ m H p T ≥ m H ‣ resummation mandatory ‣ fixed-order reliable [Plot: Grazzini] ‣ ggH point-like ‣ ggH NOT point-like ‣ bottom mass effects relevent ∞ - 10 Jonas M. Lindert

Higgs-pT: higher-order corrections full theory: loop-induced HEFT: tree-level at LO integrate-out heavy quarks Bottleneck: 
 Bottleneck: IR subtraction massive two-loop amplitudes NLO NNLO � � � � � � � ��� � � � � � � � ��� � � � � � � � ��� � � ���� ��� �� � �� ��� � � ���� ��� �� � �� ��� � � ���� ��� �� � �� ��� ������� ������� ������� [Chen et.al.; ’16] ����� ���� H ���� ��� � � ��� ��� � � [Chen et.al.; ’14+‘16 �� � �� � �� � �� ��� � � �� �������� �� � � � ���� �� ���� � �� � � � ���� Boughezal et. al.; ’15, 
 � � � ���� � � � � � � � � � ���� � � � � � ��������� ���� ��� ����� � � �� � ������������ � �� � � �� � �� � ��� Caola et.al.; ’15] g ����� � �� �� H H �� �� g ����� �� ���� � � Ansätze: � � ����� �� ��� • analytical: very hard, planar MI known ��� [Bonciani et. al., ’16] ��� ��� ��� • numerical: very CPU/GPU intensive [Jones et. al., ’18] ��� � �� ��� ��� ��� pTH �� ����� • expansions: has to be performed carefully, very versatile � � [Melnikov et. al., ’16+’17] perturb. uncertainties in HEFT under very good control: ‣ ~10% scale variation Idea: QCD corrections factorize 
 ‣ stable shapes ➜ apply K-factors from HEFT to lower order predictions in full theory ➜ check!! NNLO+NXLL 11 Jonas M. Lindert