CDF W boson mass measurement toward a new era in particle physics

Thursday 19 May 2022, 13:30 → 20:00 Asia/Seoul

서울시립대학교 자연과학연구소

Inkyu Park (University of Seoul), Jeonghyeon SONG (Konkuk University)

봄날에는 가끔씩 광기가 등을 살리는 것 같습니다. 작년 이맘때 Fermilab에서 발표한 뮤온 비정상 자기모멘트 값이 표준모형의 예측과 4.2시그마 벗어나면서 입자물리학계를 휩쓸었던 광풍이 올해 더 강력하게 돌아왔습니다. 바로 CDF에서 측정한 W 보존의 질량입니다. 전례 없는 정밀도로 측정된 W 질량값은 표준모형과 7시그마 벗어나 있습니다. CDF의 결과가 맞다면 단순히 표준모형을 뛰어넘는 이론이 필요하다는 수준을 넘어서, 그동안 광범위하게 연구된 새로운 이론들도 전혀 예상치 못한 제한을 받습니다. 이에 국내 실험물리학자와 이론물리학자가 모여서 과연 CDF의 W 보존 질량 측정의 타당성이 어느 정도인지, 향후 LHC에서는 이 불일치를 어떻게 검증할 것인지, 새로운 이론에는 어느 방향으로, 어느 정도의 제한이 있는지 심도있게 논의해 보고자 합니다. 

13:30 Registration & Reception

1 W mass measurements at Tevatron

In this talk, we review the recently published W mass measurement by the CDF II experiment. We focus on the improvement of systematic uncertainties in comparison to the previous CDF result as well as other experiments.

Speaker: Prof. Youngjoon KWON (Yonsei University)

myTalk_UoS_2022May19.pdf

2 W mass measurements at LHC

In this talk, we review the recent measurements on the W mass performed at LHC. Basic principle of the measurements at the hadron collider and major challenges will be discussed. Especially, the systematic treatments performed by the ATLAS experiment will be mainly discussed.

Speaker: Un-ki Yang (Seoul National University)

Wmass_review_LHC.pdf

15:00 Break

3 All-round attack with the CDF W boson mass on two-Higgs-doublet model

The most recent W boson mass measurement by the CDF collaboration with a substantially reduced uncertainty indicates a significant deviation from the standard model prediction. This has profound consequences in searching for physics beyond the SM. In the framework of two-Higgs-doublet models, we study the effect of the new W mass measurement on the parameter space. We impose other constraints, including theoretical requirements, flavor-changing neutral currents in physics, the cutoff scale above 1 TeV, Higgs precision data, and direct collider search limits from the LEP, Tevatron, and LHC experiments. We find that upper bounds exist on the masses of the heavy Higgs bosons. And type-II and type-Y in the inverted scenario are completely excluded. Simultaneous explanation including the muon g-2 is also discussed in the Higgs-phobic type-X.

Speaker: Prof. Jeonghyeon SONG (Konkuk University)

220519-CDF-MW-시립대.pdf

4 A case study of 2HDM in the Higgs basis

Speaker: Dr Yongtae Heo (Chonnam Natl. U.)

16:30 Break

5 A model of lepton flavor for muon g-2, W boson mass, and dark matter

We first review the status of electroweak precision after the Higgs discovery at the LHC and discuss the implications of the recent CDFII measurement of the W boson mass for precision data and new physics. We also show the interplay between muon g-2, W boson mass and dark matter in models for seesaw lepton masses with vector-like leptons and extra gauge symmetries.

Speaker: Prof. Hyunmin LEE (CAU)

6 Implications of new CDF-II W boson mass on two Higgs doublet model

We present the implications of the recent measurement of W boson at CDF II on two Higgs doublet model. In the analysis, we impose theoretical bounds such as vacuum stability and perturbative unitarity, and several experimental constraints. In addition, we take into account the measurement of sin2(mZ)MS on top of the CDF W boson mass to investigate how the S and T parameters are determined. Using the results, we show how the parameter space is constrained, and compare it with the one based on the PDG

Speaker: Prof. Sinkyu KANG (Seoul National Univeristy of Science & Technology)

18:00 Workshop dinner