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arXiv · 2009.01693

An Update to the Letter of Intent for MATHUSLA: Search for Long-Lived Particles at the HL-LHC

Abstract

We report on recent progress in the design of the proposed MATHUSLA Long Lived Particle (LLP) detector for the HL-LHC, updating the information in the original Letter of Intent (LoI), see CDS:LHCC-I-031, arXiv:1811.00927. A suitable site has been identified at LHC Point 5 that is closer to the CMS Interaction Point (IP) than assumed in the LoI. The decay volume has been increased from 20 m to 25 m in height. Engineering studies have been made in order to locate much of the decay volume below ground, bringing the detector even closer to the IP. With these changes, a 100 m x 100 m detector has the same physics reach for large c$\tau$ as the 200 m x 200 m detector described in the LoI and other studies. The performance for small c$\tau$ is improved because of the proximity to the IP. Detector technology has also evolved while retaining the strip-like sensor geometry in Resistive Plate Chambers (RPC) described in the LoI. The present design uses extruded scintillator bars read out using wavelength shifting fibers and silicon photomultipliers (SiPM). Operations will be simpler and more robust with much lower operating voltages and without the use of greenhouse gases. Manufacturing is straightforward and should result in cost savings. Understanding of backgrounds has also significantly advanced, thanks to new simulation studies and measurements taken at the MATHUSLA test stand operating above ATLAS in 2018. We discuss next steps for the MATHUSLA collaboration, and identify areas where new members can make particularly important contributions.

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Cristiano Alpigiani, Juan Carlos Arteaga-Velázquez, Austin Ball, Liron Barak, Jared Barron, Brian Batell, James Beacham, Yan Benhammo, Karen Salomé Caballero-Mora, Paolo Camarri, Roberto Cardarelli, John Paul Chou, Wentao Cui, David Curtin, Miriam Diamond, Keith R. Dienes, Liam Andrew Dougherty, Giuseppe Di Sciascio, Marco Drewes, Erez Etzion, Rouven Essig, Jared Evans, Arturo Fernández Téllez, Oliver Fischer, Jim Freeman, Jonathan Gall, Ali Garabaglu, Stefano Giagu, Stephen Elliott Greenberg, Bhawna Gomber, Roberto Guida, Andy Haas, Yuekun Heng, Shih-Chieh Hsu, Giuseppe Iaselli, Ken Johns, Audrey Kvam, Dragoslav Lazic, Liang Li, Barbara Liberti, Zhen Liu, Henry Lubatti, Lillian Luo, Giovanni Marsella, Mario Iván Martínez Hernández, Matthew McCullough, David McKeen, Patrick Meade, Gilad Mizrachi, O. G. Morales-Olivares, David Morrissey, Meny Raviv Moshe, Antonio Policicchio, Mason Proffitt, Dennis Cazar Ramirez, Matthew Reece, Steven H. Robertson, Mario Rodríguez-Cahuantzi, Albert de Roeck, Amber Roepe, Joe Rothberg, James John Russell, Heather Russell, Rinaldo Santonico, Marco Schioppa, Jessie Shelton, Brian Shuve, Yiftah Silver, Luigi Di Stante, Daniel Stolarski, Mike Strauss, David Strom, John Stupak, Martin A. Subieta Vasquez, Sanjay Kumar Swain, Guillermo Tejeda Muñoz, Steffie Ann Thayil, Brooks Thomas, Yuhsin Tsai, Emma Torro, Gordon Watts, Charles Young, Jose Zurita. 2020-09-03. An Update to the Letter of Intent for MATHUSLA: Search for Long-Lived Particles at the HL-LHC. https://arxiv.org/abs/2009.01693

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