報(bào)告時(shí)間：2026年1月23日（星期五）9:00-10:30
報(bào)告地點(diǎn)：翡翠湖校區(qū)物理樓302室
報(bào) 告 人：Giovanna Cottin 助理教授
工作單位：智利天主教大學(xué)
舉辦單位：物理學(xué)院
報(bào)告簡(jiǎn)介：
No significant deviations from the Standard Model predictions have been observed at particle physics experiments, except for neutrino masses. On the other hand, astrophysical evidence for dark matter also points to new physics. In theories beyond the Standard Model of particle physics, the new particles in the so-called dark sector can have large lifetimes, commonly referred to as long-lived particles (LLPs). These hypothetical states could travel macroscopic distances before decaying inside particle detectors, thus yielding more exotic signatures at colliders as opposed to promptly decaying states.
In this talk, I will motivate the quest for new, long-lived physics at colliders able to explain dark matter. In the models to be discussed, dark matter can come from scalar triplets, doublets or a complex singlet. It can be produced via freeze-out or freeze-in. For freeze-out, I will focus on scotogenic-like models, where neutrino masses can additionally be explained. For the latter, the impact of the cosmic reheating dynamics on dark matter freeze-in production will be discussed. All in all, new dark sector physics may be escaping detection due to its long-lived nature. I will emphasize the crucial role of (re-)interpreting long-lived particle signatures at the LHC and the proposed Future Circular Collider (FCC), and how this may help uncover the nature of the dark sector.
在粒子物理實(shí)驗(yàn)中，除了中微子質(zhì)量之外，尚未觀(guān)測(cè)到顯著偏離標(biāo)準(zhǔn)模型預(yù)言的現(xiàn)象。另一方面，天體物理學(xué)中關(guān)于暗物質(zhì)的證據(jù)同樣指向新的物理。在粒子物理超越標(biāo)準(zhǔn)模型理論中，所謂暗扇區(qū)的新粒子可能具有較長(zhǎng)的壽命，通常被稱(chēng)為長(zhǎng)壽命粒子（LLPs）。這些假想粒子態(tài)可能在粒子探測(cè)器中飛行一段宏觀(guān)距離后才衰變，因此，與迅速衰變的粒子態(tài)相比，在對(duì)撞機(jī)上會(huì)產(chǎn)生更加奇特的信號(hào)。在本報(bào)告中，我將討論在對(duì)撞機(jī)上尋找新的、能夠解釋暗物質(zhì)的長(zhǎng)壽命粒子物理及其相關(guān)動(dòng)機(jī)。在我將討論的模型中，暗物質(zhì)可能來(lái)自標(biāo)量三重態(tài)、雙重態(tài)或復(fù)單態(tài)。它可以通過(guò)凍出或凍入機(jī)制產(chǎn)生。對(duì)于 凍出而言，我將聚焦于類(lèi) scotogenic 的模型，在其中還可以同時(shí)解釋中微子質(zhì)量。對(duì)于凍入，則會(huì)討論宇宙再加熱動(dòng)力學(xué)對(duì)暗物質(zhì)凍入產(chǎn)生機(jī)制的影響?？偠灾?，新的暗扇區(qū)物理可能因?yàn)槠溟L(zhǎng)壽命而一直逃脫探測(cè)。我將強(qiáng)調(diào)在 LHC 以及未來(lái)環(huán)形對(duì)撞機(jī)（FCC）上對(duì)長(zhǎng)壽命粒子信號(hào)進(jìn)行（再）解釋所起到的關(guān)鍵作用，以及其如何幫助我們揭示暗扇區(qū)的本質(zhì)。
報(bào)告人簡(jiǎn)介：
Giovanna Cottin is an assistant professor at the Pontificia Universidad Católica de Chile. She received her Ph.D. from the University of Cambridge in 2017 and subsequently held postdoctoral positions at Taiwan University (Taiwan, China) and the Pontificia Universidad Católica de Chile (Chile) between 2017 and 2020. From 2020 to 2023, she served as an assistant professor and later an associate professor at Universidad Adolfo Ibá?ez. Since 2023, she has been an associate researcher at SAPHIR in Chile while holding a position as an assistant professor at the Pontificia Universidad Católica de Chile.
