1. Yeo Woong Yoon (Konkuk Univ.) 2015/6/2, 16 th LHC meeting @ KIAS Based on 1505.00291 In collaboration with Jeonghyeon Song(Konkuk Univ.), Sunghoon Jung (KIAS)

2. Using the Narrow Width Approximation (NWA) Production BW 2 Decay 2

3. E598, PRL (1974), SLAC, PRL (1974) Very excited moment in particle physics was when we discover a resonance peak for a new particle ATLAS, PLB (2012), CMS, PLB (2012) What if the interference effect is strong? 3

4. Large tanbeta region  Bottom and lepton Yukawa couplings are much inhanced.  Constrained by. Desert region. Currently, no experimental search for this region is available. Perturbaive is broken 4 Interference effect is important Sizable decay width For aligned 2HDM

5. Interference, one of the most striking phenomena in Quantum Mechanics.. ELECTRON GUN Roger Bach et al, New Journal of Physics (2013) 12 5

6. At the LHC CONTINUUMRESONANCE Invariant Mass Distribution Dip Nothing Peak Peak-Dip ? 6

7. 7

8. CONTINUUM RESONANCE 8

9. BW-Res. Imaginary-part Interference Real-part Interference 9

10. Interference effectively change WHAT DOES IT AFFECT PHENOMENOLOGY? Mainly.. 1. Resonance shape changes 2. NWA should be modified Also we need to consider following subtleties. Kinematic distribution of final state may be changed Smearing effect might be significant 10

11. 11

12. We meet this case for the 125GeV SM Higgs production with diphoton decay channel No complex phase in the resonance signal Complex phase in continuum affect beginning at 2loop Dixon, Siu (2003) PRL 12

13. After Gaussian smearing Real-part Interference is pure odd function: Interference only S. Martin (2012) PRD 13

14. S. Martin (2012) PRD Res. signal only Res. signal + Interference Slight shift (150 MeV) of mass peak 14

15. “Pure Dip”  BW-shape is preserved Pure Dip prefers sizable width and small R value (small signal to bg ratio). 15

16.  BW-shape is preserved “Nothingness” 16

17.  BW-shape is preserved “Pure Peak” : enhanced : suppressed 17

18. Transient Estimated by NWA We propose modified NWA as  Correction factor, and simple measure of resonance shape Cross section for production and decays : 18

19. 1. Photon collider study Asakawa, Kamoshita, Sugamoto, Watanabe (2000) EPJC Dixon, Sofianatos (2009) PRD Niezurawski, Zarnecki, Krawczyk (2002) JHEP Morris, Truong, Zappala (1994) PLB 19 Continuum bg is tree-level, Res. signal is loop level, so R is naturally loop suppressed.  Dips can arise Morris, Truong, Zappala (1994) PLB

20. 2. Hadron collider study Dicus, Willenbrock, (1988) PRD Glover, Bij (1989) NPB, Kauer, Brien 1502.04113 Campbell, Ellis, Williams (2011) JHEP 20 Both Res. signal and continuum are loop processes.  R is order 1 (quite big)  Small Im-part Interference  Mostly peak (excess) Campbell, Ellis, Williams (2011) JHEP

21.  Sizable C factor. Mostly peak shape 21 Nothingness Pure Peak For aligned 2HDM

22. Very simple and powerful parametrization for the interference effect and resonance shape. Even nothingness can happen in which Higgs can hide. 22