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    "152075-21912805":
    {
        "datetime_modified":"20260914T073549",
        "datetime_start":"20260916T150000",
        "datetime_end":"20260916T160000",
        "has_end_time":1,
        "date_start":"2026-09-16",
        "date_end":"2026-09-16",
        "time_start":"15:00:00",
        "time_end":"16:00:00",
        "time_zone":"America\/Detroit",
        "event_title":"Non-positively curved spaces",
        "occurrence_title":"",
        "combined_title":"Non-positively curved spaces: Persy Zhu",
        "event_subtitle":"Persy Zhu",
        "event_type":"Workshop \/ Seminar",
        "event_type_id":"21",
        "description":"The CAT(0) inequality says that in non-positively curved spaces triangles are no fatter than the Euclidean ones. The richest examples are symmetric spaces of non-compact type, which carry Riemannian, CAT(0), and Lie group structures at once. Using SL(n,\\R)\/SO(n) as a running example, I will explain why flats are important, and how to describe points at infinity in those spaces.  Then I'll say a bit about some work on boundaries of horospheres, and end with something hopefully interesting: dynamics on those spaces and how we use them to get counting results.",
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                "guid":"152075-21912805@events.umich.edu",
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        "room":"1866",
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        "tags":["Mathematics"],
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             {
                "group_name":"Student Dynamics\/Geometry\/Topology Seminar - Department of Mathematics",
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    {
        "datetime_modified":"20260911T113400",
        "datetime_start":"20260916T150000",
        "datetime_end":"20260916T160000",
        "has_end_time":1,
        "date_start":"2026-09-16",
        "date_end":"2026-09-16",
        "time_start":"15:00:00",
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        "time_zone":"America\/Detroit",
        "event_title":"Special HEP-Astro Seminar | Search for Dark Matter Interactions at High Recoil Energy with the LUX-ZEPLIN Experiment",
        "occurrence_title":"",
        "combined_title":"Special HEP-Astro Seminar | Search for Dark Matter Interactions at High Recoil Energy with the LUX-ZEPLIN Experiment: Sky Shi (U-M Physics)",
        "event_subtitle":"Sky Shi (U-M Physics)",
        "event_type":"Workshop \/ Seminar",
        "event_type_id":"21",
        "description":"The LUX-ZEPLIN (LZ) experiment is a dual-phase xenon time projection chamber designed to search for dark matter interactions with unprecedented sensitivity. While conventional WIMP searches focus primarily on low-energy nuclear recoils, a broader class of dark matter  models can produce significant signals at much higher recoil energies. In a new search using 2.84 tonne-years of LZ exposure, we extend the nuclear-recoil energy window to approximately 270 keV to probe momentum- and velocity-dependent interactions described by non-relativistic effective field theory, as well as inelastic dark matter models. The search observes one event in a region of low expected background, consistent with a 248 +\/- 23 (stat) +\/- 23 (sys) keVnr nuclear recoil. I will describe the motivation, methodology, and results of this extended-energy search, including the investigation of the high-energy event and possible background interpretations. I will also highlight work carried out at the University of Michigan that helped enable the extension to high recoil energies, particularly the calibration and detector-response modeling of electronic and nuclear recoils, together with studies of backgrounds relevant to the expanded search region.",
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        "tags":["Physics","Science"],
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                "group_name":"HEP - Astro Seminars",
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