Gonzalez-Iglesias, D., Aksoy, A., Esperante, D., Gimeno, B., Latina, A., Boronat, M., et al. (2021). X-band RF photoinjector design for the CompactLight project. Nucl. Instrum. Methods Phys. Res. A, 1014, 165709–10pp.
Abstract: RF photoinjectors have been under development for several decades to provide the high-brightness electron beams required for X-ray Free Electron Lasers. This paper proposes a photoinjector design that meets the Horizon 2020 CompactLight design study requirements. It consists of a 5.6-cell, X-band (12 GHz) RF gun, an emittance-compensating solenoid and two X-band traveling-wave structures that accelerate the beam out of the space-charge-dominated regime. The RF gun is intended to operate with a cathode gradient of 200 MV/m, and the TW structures at a gradient of 65 MV/m. The shape of the gun cavity cells was optimized to reduce the peak electric surface field. An assessment of the gun RF breakdown likelihood is presented as is a multipacting analysis for the gun coaxial coupler. RF pulse heating on the gun inner surfaces is also evaluated and beam dynamics simulations of the 100 MeV photoinjector are summarized.
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CLICdp Collaboration(Abramowicz, H. et al.), Boronat, M., Fullana, E., Fuster, J., Garcia, I., Gomis Lopez, P., et al. (2019). Top-quark physics at the CLIC electron-positron linear collider. J. High Energy Phys., 11(11), 003–88pp.
Abstract: The Compact Linear Collider (CLIC) is a proposed future high-luminosity linear electron-positron collider operating at three energy stages, with nominal centre-of-mass energies root s = 380 GeV, 1.5 TeV, and 3 TeV. Its aim is to explore the energy frontier, providing sensitivity to physics beyond the Standard Model (BSM) and precision measurements of Standard Model processes with an emphasis on Higgs boson and top-quark physics. The opportunities for top-quark physics at CLIC are discussed in this paper. The initial stage of operation focuses on top-quark pair production measurements, as well as the search for rare flavour-changing neutral current (FCNC) top-quark decays. It also includes a top-quark pair production threshold scan around 350 GeV which provides a precise measurement of the top-quark mass in a well-defined theoretical framework. At the higher-energy stages, studies are made of top-quark pairs produced in association with other particles. A study of ttH production including the extraction of the top Yukawa coupling is presented as well as a study of vector boson fusion (VBF) production, which gives direct access to high-energy electroweak interactions. Operation above 1 TeV leads to more highly collimated jet environments where dedicated methods are used to analyse the jet constituents. These techniques enable studies of the top-quark pair production, and hence the sensitivity to BSM physics, to be extended to higher energies. This paper also includes phenomenological interpretations that may be performed using the results from the extensive top-quark physics programme at CLIC.
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Boronat, M., Fullana, E., Fuster, J., Gomis, P., Hoang, A. H., Widl, A., et al. (2020). Top quark mass measurement in radiative events at electron-positron colliders. Phys. Lett. B, 804, 135353–9pp.
Abstract: In this letter, we evaluate the potential of linear e(+)e(-) colliders to measure the top quark mass in radiative events and in a suitable short-distance scheme. We present a calculation of the differential cross section for production of a top quark pair in association with an energetic photon from initial state radiation, as a function of the invariant mass of the t (t) over bar. This matchedcalculation includes the QCD enhancement of the cross section around the t (t) over bar production threshold and remains valid in the continuum well above the threshold. The uncertainty in the top mass determination is evaluated in realistic operating scenarios for the Compact Linear Collider (CLIC) and the International Linear Collider (ILC), including the statistical uncertainty and the theoretical and experimental systematic uncertainties. With this method, the top quark mass can be determined with a precision of 110 MeV in the initial stage of CLIC, with 1 ab(-1) at root s = 380 GeV, and with a precision of approximately 150 MeV at the ILC, with L = 4 ab(-1) at root s = 500GeV. Radiative events allow measurements of the top quark mass at different renormalization scales, and we demonstrate that such a measurement can yield a statistically significant test of the evolution of the MSR mass m(t)(MSR)(R) for scales R < m(t).
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Boronat, M., Marinas, C., Frey, A., Garcia, I., Schwenker, B., Vos, M., et al. (2015). Physical Limitations to the Spatial Resolution of Solid-State Detectors. IEEE Trans. Nucl. Sci., 62(1), 381–386.
Abstract: In this paper we explore the effect of delta-ray emission and fluctuations in the signal deposition on the detection of charged particles in silicon-based detectors. We show that these two effects ultimately limit the resolution that can be achieved by interpolation of the signal in finely segmented position-sensitive solid-state devices.
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Boronat, M., Fuster, J., Garcia, I., Roloff, P., Simoniello, R., & Vos, M. (2018). Jet reconstruction at high-energy electron-positron colliders. Eur. Phys. J. C, 78(2), 144–16pp.
Abstract: In this paper we study the performance in e(+)e(-) collisions of classical e(+)e(-) jet reconstruction algorithms, longitudinally invariant algorithms and the recently proposed Valencia algorithm. The study includes a comparison of perturbative and non-perturbative jet energy corrections and the response under realistic background conditions. Several algorithms are benchmarked with a detailed detector simulation at root s = 3 TeV. We find that the classical e(+)e(-) algorithms, with or without beam jets, have the best response, but they are inadequate in environments with non-negligible background. The Valencia algorithm and longitudinally invariant k(t) algorithms have a much more robust performance, with a slight advantage for the former.
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Andricek, L., Boronat, M., Fuster, J., Garcia, I., Gomis, P., Marinas, C., et al. (2016). Integrated cooling channels in position-sensitive silicon detectors. J. Instrum., 11, P06018–15pp.
Abstract: We present an approach to construct position-sensitive silicon detectors with an integrated cooling circuit. Tests on samples demonstrate that a very modest liquid flow very effectively cool the devices up to a power dissipation of over 10 W/cm(2). The liquid flow is found to have a negligible impact on the mechanical stability. A finite-element simulation predicts the cooling performance to an accuracy of approximately 10%.
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Abramowicz, H. et al, Boronat, M., Fuster, J., Garcia, I., Ros, E., & Vos, M. (2017). Higgs physics at the CLIC electron-positron linear collider. Eur. Phys. J. C, 77(7), 475–41pp.
Abstract: The Compact Linear Collider (CLIC) is an option for a future e(+) e(-) collider operating at centre-of-mass energies up to 3 TeV, providing sensitivity to a wide range of new physics phenomena and precision physics measurements at the energy frontier. This paper is the first comprehensive presentation of the Higgs physics reach of CLIC operating at three energy stages: root s = 350 GeV, 1.4 and 3 TeV. The initial stage of operation allows the study of Higgs boson production in Higgsstrahlung (e(+) e(-) -> ZH) and WW-fusion (e(+) e(-) -> H nu(e) (nu) over bar (e)), resulting in precise measurements of the production cross sections, the Higgs total decay width Gamma(H), and model-independent determinations of the Higgs couplings. Operation at root s > 1 TeV provides high-statistics samples of Higgs bosons produced through WW-fusion, enabling tight constraints on the Higgs boson couplings. Studies of the rarer processes e(+) e(-) -> t (t) over barH and e(+) e(-) -> HH nu(e) (nu) over bar (e) allow measurements of the top Yukawa coupling and the Higgs boson self-coupling. This paper presents detailed studies of the precision achievable with Higgs measurements at CLIC and describes the interpretation of these measurements in a global fit.
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Aplin, S., Boronat, M., Dannheim, D., Duarte, J., Gaede, F., Ruiz-Jimeno, A., et al. (2013). Forward tracking at the next e(+)e(-) collider part II: experimental challenges and detector design. J. Instrum., 8, T06001–26pp.
Abstract: We present the second in a series of studies into the forward tracking system for a future linear e(+)e(-) collider with a center-of-mass energy in the range from 250 GeV to 3 TeV. In this note a number of specific challenges are investigated, which have caused a degradation of the tracking and vertexing performance in the forward region in previous experiments. We perform a quantitative analysis of the dependence of the tracking performance on detector design parameters and identify several ways to mitigate the performance loss for charged particles emitted at shallow angle.
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DEPFET collaboration(Alonso, O. et al), Boronat, M., Esperante-Pereira, D., Fuster, J., Garcia, I. G., Lacasta, C., et al. (2013). DEPFET Active Pixel Detectors for a Future Linear e(+)e(-) Collider. IEEE Trans. Nucl. Sci., 60(2), 1457–1465.
Abstract: The DEPFET collaboration develops highly granular, ultra-transparent active pixel detectors for high-performance vertex reconstruction at future collider experiments. The characterization of detector prototypes has proven that the key principle, the integration of a first amplification stage in a detector-grade sensor material, can provide a comfortable signal to noise ratio of over 40 for a sensor thickness of 50-75 μm. ASICs have been designed and produced to operate a DEPFET pixel detector with the required read-out speed. A complete detector concept is being developed, including solutions for mechanical support, cooling, and services. In this paper, the status of the DEPFET R & D project is reviewed in the light of the requirements of the vertex detector at a future linear e(+)e(-) collider.
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Belle-II DEPFET and PXD Collaboration(Ye, H. et al), Boronat, M., Esperante, D., Fuster, J., Gomis, P., Lacasta, C., et al. (2021). Commissioning and performance of the Belle II pixel detector. Nucl. Instrum. Methods Phys. Res. A, 987, 164875–5pp.
Abstract: The Belle II experiment at the SuperKEKB energy-asymmetric e(+)e(-) collider has completed a series of substantial upgrades and started collecting data in 2019. The experiment is expected to accumulate a data set of 50 ab(-1) to explore new physics beyond the Standard Model at the intensity frontier. The pixel detector (PXD) of Belle II plays a key role in vertex determination. It has been developed using the DEpleted P-channel Field Effect Transistor (DEPFET) technology, which combines low power consumption in the active pixel area and low intrinsic noise with a very small material budget. In this paper, commissioning and performance of the PXD measured with first collision data are presented.
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