1. SM Higgs Theory Robert Harlander Bergische Universität Wuppertal
GGI, Florence, 21 April 2015
supported by

3. see talk by D. Rathlev (Wed 11.15am)
Backgrounds
huge progress at NLO due to automatic tools:
Sherpa+OpenLoops
HELAC-NLO
POWHEG-Box, GoSam, Recola, MCFM, Herwig, Pythia, ...
many NNLO and/or EW calculations:
WW, ZZ, ϒϒ, Zϒ, ttbar, ...
see talk by D. Rathlev (Wed 11.15am)

4. precision physics is coming back!

6. Towards N3LO:
Baikov, Chetyrkin, Smirnov, Smirnov, Steinhauser ’09
Lee, Smirnov, Smirnov ’10
Gehrmann, Glover, Huber, Ikizlerli, Studerus ’09
Hoschele, Hoff, Pak, Steinhauser, Ueda ’12
Anastasiou, Bühler, Duhr, Herzog ’12
O(ε)
+ Herzog ’13
Anastasiou, Duhr, Dulat, Mistlberger ’13
Boughezal, Caola, Melnikov, Petriello, Schulze ’13

7. Soft expansion:
expansion around

8. 2 lowest order terms in ambiguity:
Anastasiou, Duhr, Dulat, Furlan, Gehrmann, Herzog, Mistlberger ’13
generalization of soft N3LO to pp→Xcolor singlet
Ahmed, Mahakhud, Rana, Ravindran ’14
Catani, Cieri, de Florian, Ferrera, Grazzini ’14
ambiguity:

9. Anastasiou, Duhr, Dulat, Mistlberger ’15
30 terms:
RH, Kilgore ’02
Anastasiou, Duhr, Dulat, Mistlberger ’15

10. Anastasiou, Duhr, Dulat, Mistlberger ’15

11. +
N3LO

12. perturbative effects under control soft resummation relevant?
Consequence:
perturbative effects under control
soft resummation relevant?
need to control other effects:
bottom loops/Yukawa coupling?
mb(MH) = 2.7 GeV
mbpole = 4.7 GeV
PDFs
electro-weak effects
mass effects at NNLO

13. pT distribution

14. Consider extreme case:
Higgs does not couple to top quark
gluon-Higgs coupling mediated by Λ >> MH
measurement of total cross section
⇒ at least one of the Cn must be large!
expect very different pT spectrum
RH, Neumann ’13
Banfi, Martin, Sanz ’14
Azatov, Paul ’14
see also:
Grojean, Salvioni, Schlaffer, Weiler ’14

15. pT-shape for higher operators:
RH, Neumann ’13
NLO:
Dawson, Lewis, Zeng ’14

16. pT distribution consider gluon fusion: p1+p2=q NLO:
non-zero Higgs-pT requires emission of gluon

17. 1/mt effects
RH, Neumann, Wiesemann ’12
Neumann, Wiesemann ’14

18. threshold
ŝ>(2mt)2
ŝ<(2mt)2

19. threshold
[Marzani et al ’08]

20. (σ = φ⊗φ⊗σ) ˆ
threshold

21. exact

22. RH, Mantler, Marzani, Ozeren ’09
Pak, Rogal, Steinhauser ’09

23. inclusive H+jet:
NLO LO
Neumann, Wiesemann ’14

24. Small pT ln(pT/Q) → ∞ Q∼mH requires resummation HqT
Bozzi, Catani, de Florian, Grazzini ’03
Becher, Neubert, Wilhelm’11
de Florian, Kulesza, Vogelsang ’06
Kulesza, Sterman, Vogelsang ’03
Berger, Qiu ’03
see also:
...

25. → bottom loop effects: resummation based on collinear factorization:
pT « Q →
⊗ P +
Q = ?

26. Banfi, Monni, Zanderighi ’13
jet vetoed
Banfi, Monni, Zanderighi ’13
Mantler, Wiesemann ’12
Bagnaschi, Degrassi, Slavich, Vicini ’11
POWHEG
Hamilton, Nason, Zanderighi ’15
NNLOPS
vs. +
Grazzini, Sargsyan ’13

27. unitarity constraint:
Bozzi, Catani, de Florian, Grazzini ‘14
unitarity constraint:
may lead to dσ/dpT ≠ dσ/dpT|fixed order at large pT
RH, Mantler, Wiesemann ’14
use as prescription to determine Q!

28. produced with MoRe-SusHi

29. Conclusion on pt distribution:
1/mt effects desirable at large pT
final understanding of bottom effects still missing
detailed comparison of all approaches required
may become very important in extended theories

31. Higgs Strahlung:

32. vs. Englert, McCullough, Spannowsky ’13
see also: Hespel, Maltoni, Vryonidou ’15

33. distribution of “fat jet” (see Butterworth et al. ’08):
NNLO
Ferrera, Grazzini, Tramontano ’14 +

34. threshold resummation:
at NLO:
NLO+NLL:
RH, Kulesza, Theeuwes, Zirke
threshold resummation:
NLO: Altenkamp, Dittmaier, RH, Rzehak, Zirke ’12

35. consider ratio: σWH/σZH
very weak dependence on PDFs
very weak dependence on αS
reduced experimental uncertainties
RH, Liebler, Zirke ’13
see also:
Englert, McCullough, Spannowsky ’13
Hespel, Maltoni, Vryonidou ’15

36. 2HDM: RH, Liebler, Zirke ’13 see also:
Englert, McCullough, Spannowsky ’13
Hespel, Maltoni, Vryonidou ’15

37. ... back to SM
there is still hope: mh2 = 2λv2 ?

38. Frederix et al. ’14
see also: Baglio et al. ’13

39. effective theory for mt→∞
higher orders?
effective theory for mt→∞ →
NLO: Dawson, Dittmaier, Spira ’95
NNLO: de Florian, Mazzitelli ’13
Grigo, Melnikov, Steinhauser ’14
1/mt effects?
“like for gg→H”:
caution!

40. effective theory
expected to work
gg→HH
gg→H

41. Grigo, Hoff, Melnikov, Steinhauser ’13

42. full NLO calculation desirable...
real emission exact
virtual=EFT rescaled by Born
Maltoni, Vryonidou, Zaro ’14
full NLO calculation desirable...

43. Off-shell / interference

44. Off-shell / interference
off-shell production: handle on Higgs width
off-shell
Caola, Melnikov ’13
on-shell
see also Passarino, Kauer ’12, Campbell, Ellis, Williams ’13, ...
radiative corrections?
see talk by N. Kauer (Wed, 9am)

45. Off-shell / interference
signal / background interference: mass shift
S.P. Martin ’12
de Florian et al. ’13 γ γ

46. Lots of things I could not talk about:
NLO+PS
NNLO
ttbb signal/background interference
single top + Higgs
analysis methods
...
Hoeche et al. ’14
Ferrera, Grazzini, Tramontano ’14
Denner, Feger, Scharf ’14
Demartin, Maltoni, Mawatari, Zaro ’15
e.g. Perez, Soreq, Stamou, Tobioka ’15
... apologies!

47. Conclusions theory progress unbroken
will continue, no matter what, because:
precision physics is gradually coming back
many issues require a second glance
“only Higgs” scenario disappointing
... but good for technology!

48. full MSSM @ NLO SM @ NNLO 2HDM NMSSM bbh various ren. schemes New!
link to FeynHiggs
link to LHAPDF
link to 2HDMC
...
RH, Liebler, Mantler ’12
Liebler ’15
New!