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SUMMARY:Towards the HEFT-hedron: the complete set of positivity constraint
 s at NLO
DTSTART:20250515T130000Z
DTEND:20250515T140000Z
DTSTAMP:20260520T014300Z
UID:indico-event-1462@conference.ippp.dur.ac.uk
DESCRIPTION:Speakers: Susobhan Chattopadhyay\n\nWe present the complete se
 t of positivity bounds on the Higgs Effective Field Theory (HEFT)  at nex
 t-to-leading order (NLO). We identify the 15 operators that can be constra
 ined by positivity\, as they contribute to $s^2$-growth in the amplitude f
 or longitudinal gauge-Higgs scattering\, that is to all possible 2-to-2 sc
 attering processes involving longitudinal gauge bosons\,  $V_L = W_L^\\pm
 \, Z_L$\, and the  Higgs boson\, $h$. We find two sets of constraints: (i
 ) specific linear combinations of CP-even Wilson coefficients (WCs) must b
 e positive\, and (ii) the magnitudes of some WCs---including all CP-odd on
 es---must be smaller than products of other CP-even WCs. We present our fi
 nal constraints on the 15-dimensional HEFT space and show how known positi
 vity bounds on the 3-dimensional space of dimension 8 SMEFT can be recover
 ed from them. We find that only about $5\\%$ of the parameter space for WC
 s of HEFT operators at NLO complies with these positivity constraints.  A
 dditionally\, we obtain double-sided bounds on these WCs by fully exploiti
 ng the implications of unitarity and $st$-crossing symmetry. For WCs contr
 ibuting to the vector boson scattering process our final constraints are i
 n most cases significantly stronger than the experimental ones. For the  
  $V_L V_L\, hh \\to hh$ and $V_LV_L\, hh \\to V_Lh$ process\, there are no
  reported experimental limits and our theoretical constraints provide the 
 first  bounds.\n\nhttps://conference.ippp.dur.ac.uk/event/1462/
URL:https://conference.ippp.dur.ac.uk/event/1462/
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