split supersymmetry

split supersymmetry
Name	Split supersymmetry
Field	Theoretical physics
Introduced	2004
Proponents	Nima Arkani-Hamed; Savas Dimopoulos; Giudice; Romanello; Others
Related	Supersymmetry; Standard Model; Grand Unified Theory; String Theory

split supersymmetry Split supersymmetry is a theoretical framework in high-energy physics proposing a separation of mass scales between scalar superpartners and fermionic superpartners. It was motivated by attempts to reconcile naturalness problems in the Standard Model with experimental null results from colliders such as the Large Hadron Collider and precision constraints from experiments associated with the Tevatron and LEP. The proposal situates itself in the landscape of proposals including Supersymmetry, Grand Unified Theory, and constructions inspired by String Theory.

Overview and motivation

Split supersymmetry was motivated by tensions among results from the Large Hadron Collider, theoretical expectations from proponents like Nima Arkani-Hamed and Savas Dimopoulos, and the desire to preserve successful features of frameworks like Grand Unified Theory and Gauge coupling unification. Advocates argued that retaining fermionic superpartners such as higgsinos and gauginos could preserve phenomenology linked to the Minimal Supersymmetric Standard Model and remain compatible with precision constraints from experiments tied to ATLAS (experiment), CMS (experiment), and legacy bounds from LEP. The approach contrasts with naturalness-driven models advanced by researchers at institutions like CERN and SLAC National Accelerator Laboratory while sharing conceptual lineage with ideas from Edward Witten and approaches in String Theory compactifications.

Theoretical framework

The framework splits supersymmetric multiplets by placing scalar partners (sfermions) at very high mass scales, while fermionic partners (gauginos, higgsinos) remain near the TeV scale; this idea draws on model-building techniques developed within contexts explored by Gian Giudice and collaborators, and connects to mechanisms studied in works from groups at Harvard University, Stanford University, and University of Cambridge. Radiative corrections and renormalization group flows are analyzed using computations in the tradition of Joan Wess and Bruno Zumino; gauge coupling unification analyses reference methodologies associated with Howard Georgi and Sheldon Glashow. Mediation schemes echo classifications established by investigations at Fermilab and by researchers connected to Caltech and Princeton University.

Phenomenology and experimental signatures

Phenomenological signatures emphasize long-lived fermionic superpartners detectable at detectors such as ATLAS (experiment), CMS (experiment), and proposed detectors cited by collaborations at CERN. Phenomena include displaced vertices, missing transverse energy signals, and anomalous ionization patterns akin to searches by teams from LHCb and experimental strategies reminiscent of those used by groups at DESY and KEK. Collider limits reference analyses comparable to studies performed by Tevatron collaborations and searches guided by simulation tools developed by researchers affiliated with SLAC National Accelerator Laboratory and FNAL. Precision observables invoke comparisons to results from Muon g-2 (experiment) teams and constraints discussed in workshops involving Perimeter Institute participants.

Cosmological and astrophysical implications

Cosmological consequences involve dark matter candidates tied to fermionic superpartners such as higgsinos or winos, linking to observational programs like Planck (spacecraft), WMAP, and surveys by teams at European Space Agency and NASA. Indirect detection strategies align with searches by collaborations like Fermi Gamma-ray Space Telescope and ground arrays associated with VERITAS and H.E.S.S.. Early-universe implications intersect with baryogenesis scenarios investigated by researchers at CERN and Kavli Institute for Theoretical Physics, and with reheating and freeze-out calculations in the tradition of analyses by Alan Guth and Andrei Linde.

Model variants and extensions

Variants include configurations that embed split spectra within String Theory compactifications, constructions invoking anomaly mediation studied by groups at Princeton University and Institute for Advanced Study, and hybrids that mix gauge and gravity mediation similar to approaches developed at Yale University and University of Chicago. Extensions explore coupling to sectors motivated by Axion models researched by teams at University of California, Berkeley and by laboratories collaborating with Fermilab, and to Grand Unification patterns resembling proposals from Georgi–Glashow model-inspired work.

Constraints and current experimental status

Current constraints derive from null results in searches by ATLAS (experiment), CMS (experiment), and legacy bounds from LEP, combined with precision measurements from collaborations like the Muon g-2 (experiment) teams and cosmological limits from Planck (spacecraft). Direct detection experiments involving collaborations such as XENON and LUX-ZEPLIN (LZ) place complementary limits; indirect detection bounds are informed by analyses from Fermi Gamma-ray Space Telescope and AMS-02 (experiment). The global status reflects work by theoretical groups at CERN, Perimeter Institute, Institute for Advanced Study, and major university departments synthesizing collider, astrophysical, and cosmological data.

Open questions and future directions

Open questions include detailed UV completions within String Theory constructions pursued by researchers at Institute for Advanced Study and Stanford University, robustness of gauge coupling unification considered in studies by Howard Georgi-inspired groups, and the viability of dark matter candidates in light of forthcoming data from collaborations such as LZ, ATLAS (experiment), CMS (experiment), and Fermi Gamma-ray Space Telescope. Future directions emphasize synergies among experimental programs at CERN, observational facilities like European Southern Observatory, and theoretical efforts from institutions including Perimeter Institute and Kavli Institute for Theoretical Physics.

Category:Supersymmetry