Long live the Higgs factory: Higgs decays to long-lived particles at future lepton colliders
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摘要
We initiate the study of exotic Higgs decays to long-lived particles(LLPs) at proposed future lepton colliders, focusing on scenarios with displaced hadronic final states. Our analysis entails a realistic tracker-based search strategy involving the reconstruction of displaced secondary vertices and the imposition of selection cuts appropriate for eliminating the largest irreducible backgrounds. The projected sensitivity is broadly competitive with that of the LHC and potentially superior at lower LLP masses. In addition to forecasting branching ratio limits, which may be freely interpreted in a variety of model frameworks, we interpret our results in the parameter space of a Higgs portal Hidden Valley and various incarnations of neutral naturalness, illustrating the complementarity between direct searches for LLPs and precision Higgs coupling measurements at future lepton colliders.
We initiate the study of exotic Higgs decays to long-lived particles(LLPs) at proposed future lepton colliders, focusing on scenarios with displaced hadronic final states. Our analysis entails a realistic tracker-based search strategy involving the reconstruction of displaced secondary vertices and the imposition of selection cuts appropriate for eliminating the largest irreducible backgrounds. The projected sensitivity is broadly competitive with that of the LHC and potentially superior at lower LLP masses. In addition to forecasting branching ratio limits, which may be freely interpreted in a variety of model frameworks, we interpret our results in the parameter space of a Higgs portal Hidden Valley and various incarnations of neutral naturalness, illustrating the complementarity between direct searches for LLPs and precision Higgs coupling measurements at future lepton colliders.
We initiate the study of exotic Higgs decays to long-lived particles(LLPs) at proposed future lepton colliders, focusing on scenarios with displaced hadronic final states. Our analysis entails a realistic tracker-based search strategy involving the reconstruction of displaced secondary vertices and the imposition of selection cuts appropriate for eliminating the largest irreducible backgrounds. The projected sensitivity is broadly competitive with that of the LHC and potentially superior at lower LLP masses. In addition to forecasting branching ratio limits, which may be freely interpreted in a variety of model frameworks, we interpret our results in the parameter space of a Higgs portal Hidden Valley and various incarnations of neutral naturalness, illustrating the complementarity between direct searches for LLPs and precision Higgs coupling measurements at future lepton colliders.
引文
1G.Aad et al(ATLAS Collaboration),Phys.Lett.B,716:1-29(2012)
2 S.Chatrchyan et al(CMS Collaboration),Phys.Lett.B,716:30-61(2012)
3 CEPC Study Group collaboration,arXiv:1809.00285
4 CEPC Study Group collaboration,arXiv:1811.10545
5 M.Bicer et al(TLEP Design Study Working Group Collaboration),JHEP,01:164(2014)
6 T.Behnke,J.E.Brau,B.Foster,J.Fuster,M.Harrison,J.M.Paterson et al.,arXiv:1306.6327
7 H.Baer,T.Barklow,K.Fujii,Y.Gao,A.Hoang,S.Kanemura et al.,arXiv:1306.6352
8 M.Aicheler,P.Burrows,M.Draper,T.Garvey,P.Lebrun,K.Peach et al.,CERN-2012-007
9 J.de Blas et al.,arXiv:1812.02093
10 D.Curtin et al,Phys.Rev.D,90:075004(2014)
11 LHC Higgs Cross Section Working Group collaboration,D.de Florian et al.,arXiv:1610.07922
12 Z.Liu,L.-T.Wang,and H.Zhang,Chin.Phys.C,41:063102(2017)
13 M.J.Strassler and K.M.Zurek,Phys.Lett.B,651:374-379(2007)
14 M.J.Strassler and K.M.Zurek,Phys.Lett.B,661:263-267(2008)
15 T.Han,Z.Si,K.M.Zurek et al,JHEP,07:008(2008)
16 N.Craig,A.Katz,M.Strassler et al,JHEP,07:105(2015)
17 Y.Cui and B.Shuve,JHEP,02:049(2015)
18 D.Curtin et al.,arXiv:1806.07396
19 V.Khachatryan et al(CMS Collaboration),Phys.Rev.D,91:052012(2015)
20 ATLAS collaboration,M.Aaboud et al.,Submitted to:Phys.Rev.Lett.(2018),arXiv:1811.02542
21 LHCb collaboration,R.Aaij et al,Eur.Phys.J.C,77:812(2017)
22 L.Lee,C.Ohm,A.Soffer,and T.-T.Yu,arXiv:1810.12602
23 J.Liu,Z.Liu,and L.-T.Wang,arXiv:1805.05957
24 Y.Gershtein,Phys.Rev.D,96:035027(2017)
25 CMS collaboration,CMS-PAS-FTR-18-018
26 LHCb collaboration,LHCb-CONF-2018-006
27 C.Csaki,E.Kuflik,S.Lombardo et al,Phys.Rev.D,92:073008(2015)
28 D.Curtin and C.B.Verhaaren,JHEP,12:072(2015)
29 M.Kucharczyk and T.Wojton,CLICdp-Conf-2018-011
30 S.Antusch,E.Cazzato,and O.Fischer,JHEP,12:007(2016)
31 D.Curtin,K.Deshpande,O.Fischer et al,JHEP,07:024(2018)
32 A.Alloul,N.D.Christensen,C.Degrande et al,Comput.Phys.Commun.,185:2250-2300(2014)
33 J.Alwall,R.Frederix,S.Frixione et al,JHEP,07:079(2014)
34 T.Sjostrand,S.Mrenna,and P.Z.Skands,Comput.Phys.Commun.,178:852-867(2008)
35 DELPHES 3 collaboration,J.de Favereau,C.Delaere et al,JHEP,02:057(2014)
36 R.Brun and F.Rademakers(Nuclear Instruments and Methods in Physics Research Section A:Accelerators),Spectrometers,Detectors and Associated Equipment,389:81-86(1997)
37 CMS collaboration,V.Khachatryan et al,Phys.Rev.D,91:012007(2015)
38 FCC-ee Collaboration,FCC-ee Machine Parameters,2017(accessed December 13,2018)
39 V.Silveira and A.Zee,Phys.Lett.B,161:136-140(1985)
40 J.McDonald,Phys.Rev.D,50:3637-3649(1994)
41 C.P.Burgess,M.Pospelov,and T.ter Veldhuis,Nucl.Phys.B,619:709-728(2001)
42 X.-G.He,T.Li,X.-Q.Li et al,Phys.Rev.D,79:023521(2009)
43 M.Gonderinger,Y.Li,H.Patel,and M.J.Ramsey-Musolf,JHEP,01:053(2010)
44 Y.Mambrini,Phys.Rev.D,84:115017(2011)
45 C.Englert and M.McCullough,JHEP,07:168(2013)
46 N.Craig,C.Englert,and M.McCullough,Phys.Rev.Lett.,111:121803(2013)
47 Z.Chacko,H.-S.Goh,and R.Harnik,Phys.Rev.Lett.,96:231802(2006)
48 N.Craig,S.Knapen,and P.Longhi,Phys.Rev.Lett.,114:061803(2015)
49 G.Burdman,Z.Chacko,H.-S.Goh et al,JHEP,02:009(2007)
50 T.Cohen,N.Craig,G.F.Giudice et al,JHEP,05:091(2018)
51 H.-C.Cheng,L.Li,E.Salvioni,and C.B.Verhaaren,JHEP,05:057(2018)
1)A notable exception is CLIC, for which a study of tracker-based searches for Higgs decays to LLPs has been recently performed[29]. For preliminary studies of other non-Higgs LLP signatures at future lepton colliders, see e.g.[30]. For studies of LLP signatures at future electron-proton colliders, see[31].
2)Of course,"proper decay length"is a bit of a misnomer, but we use it as a proxy for c times the mean proper lifetimeτ.
2 S.Chatrchyan et al(CMS Collaboration),Phys.Lett.B,716:30-61(2012)
3 CEPC Study Group collaboration,arXiv:1809.00285
4 CEPC Study Group collaboration,arXiv:1811.10545
5 M.Bicer et al(TLEP Design Study Working Group Collaboration),JHEP,01:164(2014)
6 T.Behnke,J.E.Brau,B.Foster,J.Fuster,M.Harrison,J.M.Paterson et al.,arXiv:1306.6327
7 H.Baer,T.Barklow,K.Fujii,Y.Gao,A.Hoang,S.Kanemura et al.,arXiv:1306.6352
8 M.Aicheler,P.Burrows,M.Draper,T.Garvey,P.Lebrun,K.Peach et al.,CERN-2012-007
9 J.de Blas et al.,arXiv:1812.02093
10 D.Curtin et al,Phys.Rev.D,90:075004(2014)
11 LHC Higgs Cross Section Working Group collaboration,D.de Florian et al.,arXiv:1610.07922
12 Z.Liu,L.-T.Wang,and H.Zhang,Chin.Phys.C,41:063102(2017)
13 M.J.Strassler and K.M.Zurek,Phys.Lett.B,651:374-379(2007)
14 M.J.Strassler and K.M.Zurek,Phys.Lett.B,661:263-267(2008)
15 T.Han,Z.Si,K.M.Zurek et al,JHEP,07:008(2008)
16 N.Craig,A.Katz,M.Strassler et al,JHEP,07:105(2015)
17 Y.Cui and B.Shuve,JHEP,02:049(2015)
18 D.Curtin et al.,arXiv:1806.07396
19 V.Khachatryan et al(CMS Collaboration),Phys.Rev.D,91:052012(2015)
20 ATLAS collaboration,M.Aaboud et al.,Submitted to:Phys.Rev.Lett.(2018),arXiv:1811.02542
21 LHCb collaboration,R.Aaij et al,Eur.Phys.J.C,77:812(2017)
22 L.Lee,C.Ohm,A.Soffer,and T.-T.Yu,arXiv:1810.12602
23 J.Liu,Z.Liu,and L.-T.Wang,arXiv:1805.05957
24 Y.Gershtein,Phys.Rev.D,96:035027(2017)
25 CMS collaboration,CMS-PAS-FTR-18-018
26 LHCb collaboration,LHCb-CONF-2018-006
27 C.Csaki,E.Kuflik,S.Lombardo et al,Phys.Rev.D,92:073008(2015)
28 D.Curtin and C.B.Verhaaren,JHEP,12:072(2015)
29 M.Kucharczyk and T.Wojton,CLICdp-Conf-2018-011
30 S.Antusch,E.Cazzato,and O.Fischer,JHEP,12:007(2016)
31 D.Curtin,K.Deshpande,O.Fischer et al,JHEP,07:024(2018)
32 A.Alloul,N.D.Christensen,C.Degrande et al,Comput.Phys.Commun.,185:2250-2300(2014)
33 J.Alwall,R.Frederix,S.Frixione et al,JHEP,07:079(2014)
34 T.Sjostrand,S.Mrenna,and P.Z.Skands,Comput.Phys.Commun.,178:852-867(2008)
35 DELPHES 3 collaboration,J.de Favereau,C.Delaere et al,JHEP,02:057(2014)
36 R.Brun and F.Rademakers(Nuclear Instruments and Methods in Physics Research Section A:Accelerators),Spectrometers,Detectors and Associated Equipment,389:81-86(1997)
37 CMS collaboration,V.Khachatryan et al,Phys.Rev.D,91:012007(2015)
38 FCC-ee Collaboration,FCC-ee Machine Parameters,2017(accessed December 13,2018)
39 V.Silveira and A.Zee,Phys.Lett.B,161:136-140(1985)
40 J.McDonald,Phys.Rev.D,50:3637-3649(1994)
41 C.P.Burgess,M.Pospelov,and T.ter Veldhuis,Nucl.Phys.B,619:709-728(2001)
42 X.-G.He,T.Li,X.-Q.Li et al,Phys.Rev.D,79:023521(2009)
43 M.Gonderinger,Y.Li,H.Patel,and M.J.Ramsey-Musolf,JHEP,01:053(2010)
44 Y.Mambrini,Phys.Rev.D,84:115017(2011)
45 C.Englert and M.McCullough,JHEP,07:168(2013)
46 N.Craig,C.Englert,and M.McCullough,Phys.Rev.Lett.,111:121803(2013)
47 Z.Chacko,H.-S.Goh,and R.Harnik,Phys.Rev.Lett.,96:231802(2006)
48 N.Craig,S.Knapen,and P.Longhi,Phys.Rev.Lett.,114:061803(2015)
49 G.Burdman,Z.Chacko,H.-S.Goh et al,JHEP,02:009(2007)
50 T.Cohen,N.Craig,G.F.Giudice et al,JHEP,05:091(2018)
51 H.-C.Cheng,L.Li,E.Salvioni,and C.B.Verhaaren,JHEP,05:057(2018)
1)A notable exception is CLIC, for which a study of tracker-based searches for Higgs decays to LLPs has been recently performed[29]. For preliminary studies of other non-Higgs LLP signatures at future lepton colliders, see e.g.[30]. For studies of LLP signatures at future electron-proton colliders, see[31].
2)Of course,"proper decay length"is a bit of a misnomer, but we use it as a proxy for c times the mean proper lifetimeτ.