Higgs production in the MSSM: Transverse momentum resummation
Marius Wiesemann
University of Zürich
HP2 : High Precision for Hard Processes, Florence (Italy) 3-5 August, 2014
Higgs production in the MSSM : Transverse momentum resummation - - PowerPoint PPT Presentation
Higgs production in the MSSM : Transverse momentum resummation Marius Wiesemann University of Zrich HP2 : High Precision for Hard Processes, Florence (Italy) 3-5 August, 2014 Outline 1. Transverse momentum resummation 2. SM vs. MSSM Higgs
Higgs production in the MSSM: Transverse momentum resummation
Marius Wiesemann
University of Zürich
HP2 : High Precision for Hard Processes, Florence (Italy) 3-5 August, 2014
Outline
bH: NNLO+NNLL distribution in the 5FS
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 1 / 23
pT resummation
◮ production of colorless particle (mass M) ◮ problem: pT distribution diverges at pT → 0 ◮ reason: large logs ln p2 T/M2 for pT ≪ M
αs : ln(p2
T/M2), ln2(p2 T/M2)
α2
s :
ln(p2
T/M2), ln2(p2 T/M2), ln3(p2 T/M2), ln4(p2 T/M2)
· · ·
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 2 / 23
pT resummation
◮ production of colorless particle (mass M) ◮ problem: pT distribution diverges at pT → 0 ◮ reason: large logs ln p2 T/M2 for pT ≪ M
αs : ln(p2
T/M2), ln2(p2 T/M2)
α2
s :
ln(p2
T/M2), ln2(p2 T/M2), ln3(p2 T/M2), ln4(p2 T/M2)
· · ·
◮ solution: all order resummation
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 2 / 23
Transverse momentum resummation
◮ developed already 30 years ago [Parisi, Petronzio ’79], [Dokshitzer, Diakonov, Troian ’80], [Curci, Greco, Srivastava ’79], [Bassetto, Ciafaloni, Marchesini ’80], [Kodaira, Trentadue ’82], [Collins, Soper, Sterman ’85]
dσ(res)
N
dp2
T
∼
2 J0(b pT) S(b, A, B) HN fN fN, HN = HN CN CN
◮ we use newer formulation including various improvements: [Catani, de Florian, Grazzini ’01], [Bozzi, Catani, de Florian, Grazzini ’06]
◮ H embodies whole process dependence ◮ L = ln(Q2 b2/b2
0) → L′ = ln(Q2 b2/b2 0 + 1)
→ reduction of impact at high pT (low b) → unitarity constraint
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 3 / 23
Matching
◮ matched (resummed) cross section:
dp2
T
=
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 4 / 23
Matching
◮ matched (resummed) cross section:
dp2
T
=
dp2
T
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 4 / 23
Matching
◮ matched (resummed) cross section:
dp2
T
=
dp2
T
−
dp2
T
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 4 / 23
Matching
◮ matched (resummed) cross section:
dp2
T
=
dp2
T
−
dp2
T
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 4 / 23
Matching
◮ matched (resummed) cross section:
dp2
T
=
dp2
T
−
dp2
T
+
dp2
T
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 4 / 23
Matching
◮ matched (resummed) cross section:
dp2
T
=
dp2
T
−
dp2
T
+
dp2
T
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 4 / 23
Matching
◮ unitarity (due to L → L′):
T
dp2
T
≡
f.o. .
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 5 / 23
Applications
◮ SM Higgs production through gluon fusion (heavy-top limit) [Bozzi, Catani, de Florian, Grazzini ’06] ◮ Slepton pair production [Bozzi, Fuks, Klasen ’06] ◮ Vector boson pair production: WW and ZZ [Grazzini ’06], [Grazzini, Frederix ’08] ◮ Drell-Yan [Bozzi, Catani, Ferrera, de Florian, Grazzini ’10] ◮ SM Higgs production through gluon fusion with full mass
dependence
[Mantler, MW ’12], [Grazzini, Sargsyan ’13]
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 6 / 23
Applications
◮ SM Higgs production through gluon fusion (heavy-top limit) [Bozzi, Catani, de Florian, Grazzini ’06] ◮ Slepton pair production [Bozzi, Fuks, Klasen ’06] ◮ Vector boson pair production: WW and ZZ [Grazzini ’06], [Grazzini, Frederix ’08] ◮ Drell-Yan [Bozzi, Catani, Ferrera, de Florian, Grazzini ’10] ◮ SM Higgs production through gluon fusion with full mass
dependence
[Mantler, MW ’12], [Grazzini, Sargsyan ’13] ◮ Recently: Higgs production through bottom annihilation [Harlander, Tripathi, MW ’14] ◮ new: MSSM Higgs production in gluon fusion [Harlander, Mantler, MW ’14]
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 6 / 23
bH: NNLO+NNLL distribution in the 5FS
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 7 / 23
SM vs. MSSM Higgs production
[TeV] s
7 8 9 10 20 30 40 50 60 70 80
210
[pb]
10
10 1 10
210
310
LHC HIGGS XS WG 2014 H ( N N L O + N N L L Q C D + N L O E W )= 125 GeV
HM MSTW2008
◮ SM:
◮ gluon fusion by far
dominant
◮ b¯
bH sizeable only with b-tagging
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 8 / 23
SM vs. MSSM Higgs production
[TeV] s
7 8 9 10 20 30 40 50 60 70 80
210
[pb]
10
10 1 10
210
310
LHC HIGGS XS WG 2014 H ( N N L O + N N L L Q C D + N L O E W )= 125 GeV
HM MSTW2008
◮ SM:
◮ gluon fusion by far
dominant
◮ b¯
bH sizeable only with b-tagging
◮ MSSM/2HDM:
◮ 3 neutral Higgs: h, H and A ◮ yb/yt enhanced by tan β ◮ h: constrained to be SM-like ◮ b¯
bH/A dominant for large tan β
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 8 / 23
Associated H(b¯ b) production
4-flavour scheme 5-flavour scheme
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 9 / 23
Associated H(b¯ b) production
4-flavour scheme
◮ exclusive up to NLO [Dittmaier, Krämer, Spira ’04] [Dawson, Jackson, Reina, Wackeroth ’04]
5-flavour scheme
◮ inclusive up to NNLO [Harlander, Kilgore ’03] ◮ exclusive up to NNLO [Buehler, Herzog, Lazopoulos, Mueller ’12] ◮ NLO+NLL pT resummation [Belyaev, Nadolsky, Yuan ’06]
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 9 / 23
bH: NNLO+NNLL distribution in the 5FS
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 10 / 23
b¯ bH: Ingredients of the calculation
dp2
T
=
dp2
T
◮ analytic pT-distribution [Ozeren ’10]
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 11 / 23
αs:
❜ ❜α2
s:
❜ ❜b b
b¯ bH: Ingredients of the calculation
dp2
T
=
dp2
T
−
dp2
T
◮ analytic pT-distribution [Ozeren ’10] ◮ resummation coefficients from Drell-Yan
A(1), A(2), B(1) [Kodaira, Trentadue ’82], C(1) [Davies, Stirling ’84], A(3) [Becher, Neubert ’11], C(2) (H(2)) [Catani, Cieri, de Florian, Grazzini ’12]
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 11 / 23
b¯ bH: Ingredients of the calculation
dp2
T
=
dp2
T
−
dp2
T
◮ analytic pT-distribution [Ozeren ’10] ◮ resummation coefficients from Drell-Yan
A(1), A(2), B(1) [Kodaira, Trentadue ’82], C(1) [Davies, Stirling ’84], A(3) [Becher, Neubert ’11], C(2) (H(2)) [Catani, Cieri, de Florian, Grazzini ’12]
◮ Hb¯ bH(1) = 3 CF ◮ new: [Harlander, Tripathi, MW ’14]
Hb¯
bH(2) = 10.47 ± 0.08 (numerical result)
Hb¯
bH(2) = CF 321 64 − 13 48π2
CF +
288 + π2 12
+
576 − 5 12π2 − 9 4ζ3
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 11 / 23
from universal form of H(2) [Catani, Cieri, de Florian, Grazzini ’13]
→ see Leandro’s talk
b b
b¯ bH: Ingredients of the calculation
dp2
T
=
dp2
T
−
dp2
T
◮ analytic pT-distribution [Ozeren ’10] ◮ resummation coefficients from Drell-Yan
A(1), A(2), B(1) [Kodaira, Trentadue ’82], C(1) [Davies, Stirling ’84], A(3) [Becher, Neubert ’11], C(2) (H(2)) [Catani, Cieri, de Florian, Grazzini ’12]
◮ Hb¯ bH(1) = 3 CF ◮ new: [Harlander, Tripathi, MW ’14]
Hb¯
bH(2) = 10.47 ± 0.08 (numerical result)
Hb¯
bH(2) = CF 321 64 − 13 48π2
CF +
288 + π2 12
+
576 − 5 12π2 − 9 4ζ3
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 11 / 23
from universal form of H(2) [Catani, Cieri, de Florian, Grazzini ’13]
→ see Leandro’s talk
b b
b¯ bH: Ingredients of the calculation
dp2
T
=
dp2
T
−
dp2
T
+
dp2
T
◮ analytic pT-distribution [Ozeren ’10] ◮ resummation coefficients from Drell-Yan
A(1), A(2), B(1) [Kodaira, Trentadue ’82], C(1) [Davies, Stirling ’84], A(3) [Becher, Neubert ’11], C(2) (H(2)) [Catani, Cieri, de Florian, Grazzini ’12]
◮ + Hb¯ bH(1) and Hb¯ bH(2) ◮ third term: modified version of HqT
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 11 / 23
[Bozzi, Catani, de Florian, Grazzini ’03 ’05] [de Florian, Ferrera, Grazzini, Tommasini ’11]
b¯ bH: Checks
◮ analytic pT-distribution checked against numerical H + jet
calculation at NLO [Harlander, Ozeren, MW ’10]
◮ unitarity:
dpT dpT = total
◮ for various µF, µR values ◮ integral Qres-independent
◮ fixed order (pT → 0) = logs (pT → 0)
◮ for various µF, µR values ◮ independent of Qres
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 12 / 23
b¯ bH: Results
NLO+NLL distribution:
[Harlander, Tripathi, MW ’14], [Belyaev, Nadolsky, Yuan ’06]
dp2
T=
dp2
T−
dp2
T+
dp2
T(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 13 / 23
Q = mH/2 Q = mH/4
b¯ bH: Results
NLO+NLL distribution:
[Harlander, Tripathi, MW ’14], [Belyaev, Nadolsky, Yuan ’06]
dp2
T=
dp2
T−
dp2
T+
dp2
T(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 13 / 23
higher order effect! [Banfi, Monni, Zanderighi ’13] Q = mH/2 Q = mH/4
b¯ bH: Results
NNLO+NNLL distribution:
[Harlander, Tripathi, MW ’14]
dp2
T=
dp2
T−
dp2
T+
dp2
T(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 14 / 23
Q = mH/4
b¯ bH: Results
Scale uncertainties:
[Harlander, Tripathi, MW ’14]
dp2
T=
dp2
T−
dp2
T+
dp2
T(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 15 / 23
Q-variation Q+µF+µR- variation
b¯ bH: Results
Comparison to 5FS NLO+PS:
[Frederix, Frixione, Maltoni, Torielli, MW]
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 16 / 23
Preliminary analytic resum: µF = µR = mT/4 NLO+PS: µF = µR = HT/4
b¯ bH: Results
Comparison to 4FS NLO+PS:
[Frederix, Frixione, Maltoni, Torielli, MW]
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 17 / 23
Preliminary analytic resum: µF = µR = mT/4 NLO+PS: µF = µR = HT/4
b¯ bH: Results
Comparison to 4FS NLO+PS:
[Frederix, Frixione, Maltoni, Torielli, MW]
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 17 / 23
Preliminary → Qshower significantly lower than Higgs mass (peak around 45 GeV , similar to µF) (default shower scale in MG5_aMC distribution peaks around 190 GeV) analytic resum: µF = µR = mT/4 NLO+PS: µF = µR = HT/4
bH: NNLO+NNLL distribution in the 5FS
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 18 / 23
Gluon fusion: Ingredients of the calculation
◮ NNLO+NNLL in heavy-top limit [Bozzi, Catani, de Florian, Grazzini ’05] ◮ MSSM effects? → new: MoRe-SusHi (on sushi.hepforge.org)
dσ dpT = dσf.o. dpT − dσlogs dpT + dσres dpT
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 19 / 23
Gluon fusion: Ingredients of the calculation
◮ NNLO+NNLL in heavy-top limit [Bozzi, Catani, de Florian, Grazzini ’05] ◮ MSSM effects? → new: MoRe-SusHi (on sushi.hepforge.org)
dσ dpT = dσf.o. dpT − dσlogs dpT + dσres dpT
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 19 / 23
Amplitudes from SusHi
[Harlander, Liebler, Mantler ’12]
Gluon fusion: Ingredients of the calculation
◮ NNLO+NNLL in heavy-top limit [Bozzi, Catani, de Florian, Grazzini ’05] ◮ MSSM effects? → new: MoRe-SusHi (on sushi.hepforge.org)
dσ dpT = dσf.o. dpT − dσlogs dpT + dσres dpT
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 19 / 23
σ(0)
t+b
Amplitudes from SusHi
[Harlander, Liebler, Mantler ’12]
Gluon fusion: Ingredients of the calculation
◮ NNLO+NNLL in heavy-top limit [Bozzi, Catani, de Florian, Grazzini ’05] ◮ MSSM effects? → new: MoRe-SusHi (on sushi.hepforge.org)
dσ dpT = dσf.o. dpT − dσlogs dpT + dσres dpT H
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 19 / 23
, etc. σ(0)
t+b
φ φ
Amplitudes from SusHi
[Harlander, Liebler, Mantler ’12]
Gluon Fusion: Results
NLO+NLL ratio in the MSSM/SM (light Higgs):
[Harlander, Mantler, MW ’14]
RS(pT) = dσS/dpT
dσSM/dpT
NS(pT) = dσS/dpT
dσSM/dpT · σSM σS
0.9 0.92 0.94 0.96 0.98 1 50 100 150 200 250 300 RS(pT) pT [GeV] pp @ 13 TeV tauphobic(800,16) tauphobic(800,29.5) mhmax(300,6.5) mhmodp(500,17) mhmodm(500,16.5) lightstau(500,12) 0.9 0.92 0.94 0.96 0.98 1 50 100 150 200 250 300 RS(pT) pT [GeV] pp @ 13 TeV 0.96 0.98 1 1.02 1.04 50 100 150 200 250 300 NS(pT) pT [GeV] pp @ 13 TeV tauphobic(800,16) tauphobic(800,29.5) mhmax(300,6.5) mhmodp(500,17) mhmodm(500,16.5) lightstau(500,12) 0.96 0.98 1 1.02 1.04 50 100 150 200 250 300 NS(pT) pT [GeV] pp @ 13 TeV
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 20 / 23
ratio to SM shape-ratio to SM
Benchmark Scenarios from [Carena, Heinemeyer, Stål, Wagner, Weiglein ’13]
light Higgs light Higgs
Gluon Fusion: Results
10-7 10-6 10-5 50 100 150 200 250 300 dσ/dpT [pb/GeV] pT tauphobic, mA = 800 GeV tan(β) = 16 tan(β) = 29.5 10-6 10-5 10-4 50 100 150 200 250 300 dσ/dpT [pb/GeV] pT tauphobic, mA = 800 GeV tan(β) = 16 tan(β) = 29.5 10-7 10-6 10-5 10-4 50 100 150 200 250 300 dσ/dpT [pb/GeV] pT mhmodm, mA = 800 GeV tan(β) = 17 tan(β) = 40 10-7 10-6 10-5 10-4 50 100 150 200 250 300 dσ/dpT [pb/GeV] pT [GeV] 10-6 10-5 10-4 50 100 150 200 250 300 dσ/dpT [pb/GeV] pT mhmodm, mA = 800 GeV tan(β) = 17 tan(β) = 40 10-6 10-5 10-4 50 100 150 200 250 300 dσ/dpT [pb/GeV] pT [GeV](University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 21 / 23
heavy Higgs pseudo-scalar heavy Higgs pseudo-scalar
Gluon Fusion: Results
NLO+NLL distribution in the MSSM (left: heavy, right: pseudo-scalar):
[Harlander, Mantler, MW ’14]
NS(pT) = dσS/dpT
dσSM/dpT · σSM σS
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 50 100 150 200 250 300 NS(pT) pT [GeV] pp @ 13 TeV tauphobic(800,16) tauphobic(800,29.5) mhmodp(800,17) mhmodp(800,40) mhmodm(800,16.5) mhmodm(800,40) 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 50 100 150 200 250 300 NS(pT) pT [GeV] pp @ 13 TeV 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 50 100 150 200 250 300 NS(pT) pT [GeV] pp @ 13 TeV tauphobic(800,16) tauphobic(800,29.5) mhmodp(800,17) mhmodp(800,40) mhmodm(800,16.5) mhmodm(800,40) 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 50 100 150 200 250 300 NS(pT) pT [GeV] pp @ 13 TeV
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 22 / 23
heavy Higgs pseudo-scalar
Conclusions and Outlook
Conclusions:
◮ b¯
bH and gluon fusion crucial in MSSM/2HDM b¯ bH:
◮ missing hard coefficient at two-loop for H(b¯
b) determined
◮ first calculation of NNLL pT-effects for H(b¯
b) production
◮ strong reduction of resummation scale dependence ◮ consistent with NLO+PS results ◮ remarkable agreement of 5FS NNLO+NNLL with 4FS NLO+PS
gluon fusion:
◮ MoRe-SusHi: MSSM effects included in analytic resummation ◮ h: quite SM-like ◮ H/A: significant shape/normalization distortion from b-loop
Outlook:
◮ first NLO+PS in 4FS ◮ complete differential comparison 4FS and 5FS for H(b¯
b)
◮ inclusion of b¯
bH into MoRe-SusHi
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 23 / 23
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 1 / 11
Resummation coefficients: determination of Hb¯
bH,(2) b
◮ hard-collinear function:
Hb¯
bH(2) b¯ b←b¯ b(z) = Hb¯ bH(2) b
δ(1 − z) + known
◮ use unitarity:
σ(tot)
b¯ b
T
b
dp2
T
−
dσ(res)
b¯ b
dp2
T
f.o.
+
T
dσ(res)
b¯ b
dp2
T
l.a.
σ(0)
b¯ b Hb¯ bH(2) b¯ b←b¯ b
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 2 / 11
[Catani, Cieri, de Florian, Ferrera, Grazzini ’12]
Resummation coefficients: determination of Hb¯
bH,(2) b
◮ hard-collinear function:
Hb¯
bH(2) b¯ b←b¯ b(z) = Hb¯ bH(2) b
δ(1 − z) + known
◮ use unitarity:
σ(tot)
b¯ b
T
b
dp2
T
−
dσ(res)
b¯ b
dp2
T
f.o.
+
T
dσ(res)
b¯ b
dp2
T
l.a.
σ(0)
b¯ b Hb¯ bH(2) b¯ b←b¯ b
→ numerical result: Hb¯
bH,(2) b
= 10.47 ± 0.08
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 2 / 11
[Catani, Cieri, de Florian, Ferrera, Grazzini ’12]
Resummation coefficients: determination of Hb¯
bH,(2) b
→ numerical result: Hb¯
bH,(2) b
= 10.47 ± 0.08
◮ recently: universal Form of H(2) determined [Catani, Cieri, de Florian, Grazzini ’13]
→ for both gg- and q¯ q-initiated processes → process dependence: finite part of virtuals
◮ anlytical result from two-loop virtuals: [Harlander, Tripathi, MW ’14]
Hb¯
bH,(2) b
= CF
321
64 − 13 48π2
288 + π2 12
+
5269
576 − 5 12π2 − 9 4ζ3
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 3 / 11
Results
PDF+αs uncertainties:
[Harlander, Tripathi, MW ’14]
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 4 / 11
b¯ bH: Results
Q = mH/2 vs. Q = mH/4:
[Harlander, Tripathi, MW ’14]
dp2
T=
dp2
T−
dp2
T+
dp2
T(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 5 / 11
pT resummation
◮ determination of resummation coefficients:
◮ expand resummation formula in αs ◮ compare to small pT region of fixed order cross section ◮ Q0 ≪ M:
αs :
Q2
dp2
T
dp2
T !
=
Q2
dp2
T
dp2
T
f (A(1), B(1), C(1), H(1)) = K2 ln2(Q2
0/M2) + K1 ln(Q2 0/M2) + K0
+ O(Q2
0/M2) ◮ known for Drell-Yan and gg → H up to NNLL [Kodaira, Trentadue ’82], [Davies, Stirling ’84], [Catani, D’Emilio, Trentadue ’88], [de Florian, Grazzini ’01], [Becher, Neubert ’11], [Catani, Grazzini ’11], [Catani, Cieri, de Florian, Ferrera, Grazzini ’12]
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 6 / 11
Gluon fusion: Choosing the resummation scale
◮ Qb ≡ Qtb = mb in SM suggested due to appearance of terms [Grazzini, Sargsyan ’13]
∼ ln(mb/pT)
◮ vanish as pT → 0 ⇒ no factorization breaking, no Sudakov logs ◮ directly related to ln(mb/mH) in total rate ◮ HOWEVER: could spoil collinear/soft approximation
⇒ Sudakov resummation would be unsufficient
◮ BUT: if small, treated as all other finite terms (power
corrections in pT)
◮ choosing Qb (and Qtb) – 2 proposals:
[Banfi, Monni, Zanderighi ’13]
[Bagnaschi, Vicini]
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 7 / 11 2 2
H pt mb
H
Gluon fusion: Choosing the resummation scale
◮ bad high pT matching for large Q ◮ due to unitarity: cross section will even become negative ◮ pragmatic way to determine Q: [Harlander, Mantler, MW ’14]
require that cross section remains positive for Q = 2 Q0
0.5 1 1.5 2 100 150 200 250 300 350 400 (dσres/dpT) / (dσfo/dpT) pT [GeV] Qres = 94 GeV Qres = 96 GeV Qres = 98 GeV Qres = 100 GeV Qres = 102 GeV 0.5 1 1.5 2 100 150 200 250 300high pT matching → Qt = 49 GeV, Qb = 23 GeV, Qtb = 34 GeV
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 8 / 11
top bottom interference
Gluon fusion: Choosing the resummation scale
◮ bad high pT matching for large Q ◮ due to unitarity: cross section will even become negative ◮ pragmatic way to determine Q: [Harlander, Mantler, MW ’14]
require that cross section remains positive for Q = 2 Q0
0.5 1 1.5 2 100 150 200 250 300 350 400 (dσres/dpT) / (dσfo/dpT) pT [GeV] Qres = 94 GeV Qres = 96 GeV Qres = 98 GeV Qres = 100 GeV Qres = 102 GeV 0.5 1 1.5 2 100 150 200 250 300high pT matching → Qt = 49 GeV, Qb = 23 GeV, Qtb = 34 GeV finite terms (for pveto
T
) → Qt ∼ 60 GeV, Qb ≡ Qtb ∼ 35 GeV soft/collinear approx (10%) → Qt ∼ 55 GeV, Qb ∼ 25 GeV
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 8 / 11
top bottom interference
◮ considered for pjet T,veto efficiencies [Banfi, Monni, Zanderighi ’13]
finite terms ≤ 50% → Qt ∼ 60 GeV, Qb ≡ Qtb ∼ 35 GeV
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 9 / 11 0.2 0.4 0.6 0.8 1 1 10 100 εremainder(pt,veto)/εremainder(pt,veto=∞) pt,veto [GeV]
mH = 125 GeV mt = 173.5 GeV; mb = 4.65 GeV| t |2 | b |2+2 Re[b*⋅ t] | t+b |2
◮ at matrixelement level for pT Higgs → more in Alessandro’s talk [Bagnaschi, Vicini]
max 10% deviation → Qt ∼ 55 GeV, Qb ∼ 25 GeV
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 10 / 11
50 100 150 200 250 300 eVL 0.8 1.0 1.2 1.4 C 50 100 150 200 250 300 ptH HGeVL 0.8 1.0 1.2 1.4 C 50 100 150 200 250 300 eVL 0.8 1.0 1.2 1.4 CX
λ1,λ2,λ3=±1
50 100 150 200 250 300 ptH 0.8 1.0 1.2 1.4 50 100 150 200 250 300 ptH 0.8 1.0 1.2 1.4 Ct-only b-only
Gluon Fusion: Results
NLO+NLL distribution in the SM:
[Harlander, Mantler, MW ’14]
dp2
T=
dp2
T−
dp2
T+
dp2
T10-4 10-3 10-2 10-1 100 50 100 150 200 250 300 dσ/dpT [pb/GeV] pT [GeV] SM, mH = 125.6 GeV, pp @ 13 TeV SM f.o. 0.7 0.8 0.9 1 1.1 1.2 1.3 50 100 150 200 250 300 (dσx/dpT) / (dσhtl/dpT) pT [GeV] pp @ 13 TeV b+t t
(University of Zürich) Higgs pT spectrum in the MSSM September 5, 2014 11 / 11