MSMartin Schürmann

Martin Schürmann

*This is an algorithmically generated author record based on publicly available information.

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Previous Organizations / Institutes

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Martin Schürmann has a total of 48 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    The ABC of RPV. Part II. Classification of R-parity violating signatures from UDD couplings and their coverage at the LHC

    by Herbi K. Dreiner, Michael Hank, Yong Sheng Koay, Martin Schürmann, Rhitaja Sengupta, Apoorva Shah, Nadja Strobbe, Evelyn Thomson

    We perform a detailed study of the current phenomenological status of baryon number violating operators within the framework of the R-parity violating Minimal Supersymmetric Standard Model (RPV-MSSM). This study aims to identify any gaps in the experimental coverage of the RPV landscape. We identify the unique final states for all possible LSPs decaying via four different benchmark UDD operators. Both the direct production of the LSP and its production via gauge-cascades are considered. For each LSP, we assume that only one UDD coupling is non-zero at a time and confront the signals with existing ATLAS and CMS searches implemented in the recasting framework CheckMATE 2. We find that the UDD colored LSP sector is well covered with the mass bounds on the gluino LSP being the strongest, and with possible improvements for some of the right-handed squark LSPs. We also point out that there is limited coverage for electroweakino and slepton LSPs with UDD decays. This limitation may be due to the lack of targeted experimental searches for these specific final states or the appropriate recasting of existing searches.


  • Open Access

    A proposal for the Lohengrin experiment to search for dark sector particles at the ELSA Accelerator

    by Philip Bechtle, Christian Bespin, Dominique Breton, Carlos Orero Canet, Klaus Desch, Herbi Dreiner, Oliver Freyermuth, Rhorry Gauld, Markus Gruber, César Blanch Gutiérrez, et al.

    We present a proposal for a future light dark matter search experiment at the Electron Stretcher Accelerator ELSA in Bonn: Lohengrin. It employs the fixed-target missing momentum based technique for searching for dark-sector particles. The Lohengrin experiment uses a beam of electrons that is extracted from the ELSA accelerator and that is shot onto a thin target to produce mainly Standard Model bremsstrahlung and – in rare occasions – possibly new particles coupling feebly to the electron. A well motivated candidate for such a new particle is the dark photon, a new, possibly massive gauge boson arising from a new gauge interaction in a dark sector and mixing kinetically with the Standard Model photon. The Lohengrin experiment is estimated to reach sensitivity to couplings small enough to explain the relic abundance of dark matter in various models for dark photon masses between $$\sim 1 $$ ∼ 1 and $$\sim {100\,\mathrm{\text {M}\text {eV}}}$$ ∼ 100 M .


  • Open Access

    Recasting bounds on long-lived heavy neutral leptons in terms of a light supersymmetric R-parity violating neutralino

    by Herbi K. Dreiner, Dominik Köhler, Saurabh Nangia, Martin Schürmann, Zeren Simon Wang

    In R-parity-violating (RPV) supersymmetric models, light neutralinos with masses from the GeV-scale down to even zero are still allowed by all laboratory constraints. They are further consistent with dark matter observations, as they decay via RPV couplings. These RPV couplings are in general constrained to be small. Hence, such light neutralinos, if produced, e.g., at a beam-dump or collider experiment, appear as displaced vertices or missing energy at the detector level. The same signatures have been extensively searched for at various experiments in the theoretical context of sterile neutrinos which mix with active neutrinos. In this work, we recast the sensitivity of both past and present experiments to sterile neutrinos to obtain new bounds on RPV couplings associated with a light neutralino. We find experiments such as T2K, BEBC, FASER, DUNE, and MoEDAL-MAPP can improve the current bounds on RPV couplings by up to 3–4 orders of magnitude in several benchmark scenarios.


  • Open Access

    Recasting Bounds on Long-lived Heavy Neutral Leptons in Terms of a Light Supersymmetric R-parity Violating Neutralino

    by Herbi K. Dreiner, Dominik Köhler, Saurabh Nangia, Martin Schürmann, Zeren Simon Wang

    In R-parity-violating (RPV) supersymmetric models, light neutralinos with masses from the GeV-scale down to even zero are still allowed by all laboratory constraints. They are further consistent with dark matter observations, as they decay via RPV couplings. These RPV couplings are in general constrained to be small. Hence, such light neutralinos, if produced, e.g., at a beam-dump or collider experiment, appear as displaced vertices or missing energy at the detector level. The same signatures have been extensively searched for at various experiments in the theoretical context of sterile neutrinos which mix with active neutrinos. In this work, we recast the sensitivity of both past and present experiments to sterile neutrinos to obtain new bounds on RPV couplings associated with a light neutralino. We find experiments such as T2K, BEBC, FASER, DUNE, and MoEDAL-MAPP can improve the current bounds on RPV couplings by up to $3-4$ orders of magnitude in several benchmark scenarios.

  • Open Access

    Calibration problems with the viscosity measurement of liquid metallurgical slags

    by H P Heller, M Schürmann, K Scholl, N Haustein, B Lychatz, J Falkus

    The viscosity of slag is an important characteristic of liquid slags regarding its lubricating effect and mass transfer. For measurement, however, they exhibit considerable differences in the values reported. Therefore, the rotation method, mostly used for high temperatures areas, is investigated regarding the impacts of any geometric inaccuracies. Furthermore, problems in the centering and use of calibration slags are discussed. It appears that, with the use of a more precise rheometer with air bearing, an error of less than +/- 3 % is possible in compliance with geometric critical values and online monitoring of the central operations. The verification was carried out with a blast furnace slag, which is also proposed as a calibration slag.


  • Structure determination of three-dimensional hafnium silicide nano structures on Si(100) by means of X-ray photoelectron diffraction

    by C.R. Flüchter, A. de Siervo, D. Weier, M. Schürmann, A. Beimborn, S. Dreiner, M.F. Carazzolle, R. Landers, G.G. Kleiman, C. Westphal