| Records |
| Author |
Babeluk, M. et al; Marinas, C. |
| Title |
CMOS MAPS upgrade for the Belle II Vertex Detector |
Type |
Journal Article |
| Year |
2023 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
| Volume |
1048 |
Issue |
|
Pages |
168015 - 5pp |
| Keywords |
Belle II; VXD; SVD; PXD; VTX; Upgrade; CMOS; DMAPS |
| Abstract |
The success of the Belle II experiment in Japan relies on the very high instantaneous luminosity, close to 6x1035 cm-2 s-1, expected from the SuperKEKB collider. The corresponding beam conditions at such luminosity levels generate large rates of background particles and creates stringent constraints on the vertex detector, adding to the physics requirements. Current prospects for the occupancy rates in the present vertex detector (VXD) at full luminosity fall close to the acceptable limits and bear large uncertainties. In this context, the Belle II collaboration is considering the possibility to install an upgraded VXD system around 2027 to provide a sufficient safety margin with respect to the expected background rate and possibly enhance tracking and vertexing performance. The VTX collaboration has started the design of a fully pixelated VXD, called VTX, based on fast and highly granular Depleted Monolithic Active Pixel Sensors (DMAPS) integrated on light support structures. The two main technical features of the VTX proposal are the usage of a single sensor type over all the layers of the system and the overall material budget below 2% of radiation length, compared to the current VXD which has two different sensor technologies and about 3% of radiation length. A dedicated sensor (OBELIX), taylored to the specific needs of Belle II, is under development, evolving from the existing TJ-Monopix2 sensor. The time-stamping precision below 100 ns will allow all VTX layers to take part in the track finding strategy contrary to the current situation. The first two detection layers are designed according to a self-supported all-silicon ladder concept, where 4 contiguous sensors are diced out of a wafer, thinned and interconnected with post-processed redistribution layers. The outermost detection layers follow a more conventional approach with a cold plate and carbon fibre support structure, and light flex cables interconnecting the sensors. This document will review the context, technical details and development status of the proposed Belle II VTX. |
| Address |
[Babeluk, M.; Bergauer, T.; Irmler, C.; Schwanda, C.] Austrian Acad Sci, Inst High Energy Phys, A-1050 Vienna, Austria, Email: christian.wessel@desy.de |
| Corporate Author |
|
Thesis |
|
| Publisher |
Elsevier |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
ISSN  |
0168-9002 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000990246200001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5538 |
| Permanent link to this record |
| |
|
| |
| Author |
Natochii, A. et al; Marinas, C. |
| Title |
Measured and projected beam backgrounds in the Belle II experiment at the SuperKEKB collider |
Type |
Journal Article |
| Year |
2023 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
| Volume |
1055 |
Issue |
|
Pages |
168550 - 21pp |
| Keywords |
Detector background; Lepton collider; Monte-Carlo simulation |
| Abstract |
The Belle II experiment at the SuperKEKB electron-positron collider aims to collect an unprecedented data set of 50 ab-1 to study CP-violation in the B-meson system and to search for Physics beyond the Standard Model. SuperKEKB is already the world's highest-luminosity collider. In order to collect the planned data set within approximately one decade, the target is to reach a peak luminosity of 6 x 1035 cm-2 s-1by further increasing the beam currents and reducing the beam size at the interaction point by squeezing the betatron function down to betay* = 0.3 mm. To ensure detector longevity and maintain good reconstruction performance, beam backgrounds must remain well controlled. We report on current background rates in Belle II and compare these against simulation. We find that a number of recent refinements have significantly improved the background simulation accuracy. Finally, we estimate the safety margins going forward. We predict that backgrounds should remain high but acceptable until a luminosity of at least 2.8 x 1035 cm-2 s-1is reached for betay* = 0.6 mm. At this point, the most vulnerable Belle II detectors, the Time-of-Propagation (TOP) particle identification system and the Central Drift Chamber (CDC), have predicted background hit rates from single-beam and luminosity backgrounds that add up to approximately half of the maximum acceptable rates. |
| Address |
[Natochii, A.; Browder, T. E.; Schueler, J.; Vahsen, S. E.] Univ Hawaii, Honolulu, HI 96822 USA, Email: natochii@hawaii.edu; |
| Corporate Author |
|
Thesis |
|
| Publisher |
Elsevier |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0168-9002 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:001056103200001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5626 |
| Permanent link to this record |
| |
|
| |
| Author |
Belle II Collaboration (Adachi, I. et al); Gomis, P.; Marinas, C. |
| Title |
Search for an Invisibly Decaying Z ' Boson at Belle II in e(+)e(-) -> mu(+)mu(-) (e(+/-)mu(-/+)) Plus Missing Energy Final States |
Type |
Journal Article |
| Year |
2020 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
| Volume |
124 |
Issue |
14 |
Pages |
141801 - 9pp |
| Keywords |
|
| Abstract |
Theories beyond the standard model often predict the existence of an additional neutral boson, the Z'. Using data collected by the Belle II experiment during 2018 at the SuperKEKB collider, we perform the first searches for the invisible decay of a Z' in the process e(+)e(-) -> mu(+)mu(-) Z' and of a lepton-flavor-violating Z' in e(+) e(-) -> e(+/-)mu(-/+)Z'. We do not find any excess of events and set 90% credibility level upper limits on the cross sections of these processes. We translate the former, in the framework of an L, – L, theory, into upper limits on the Z' coupling constant at the level of 5 x 10(-2) – 1 for M-z' <= 6 GeV/c(2). |
| Address |
[Jia, S.; Shen, C. P.; Zhou, X. Y.] Beihang Univ, Beijing 100191, Peoples R China |
| Corporate Author |
|
Thesis |
|
| Publisher |
Amer Physical Soc |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0031-9007 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000523637800002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4362 |
| Permanent link to this record |
| |
|
| |
| Author |
Belle II Collaboration (Abudinen, F. et al); Gomis, P.; Marinas, C. |
| Title |
Search for Axionlike Particles Produced in e(+)e(-) Collisions at Belle II |
Type |
Journal Article |
| Year |
2020 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
| Volume |
125 |
Issue |
16 |
Pages |
161806 - 9pp |
| Keywords |
|
| Abstract |
We present a search for the direct production of a light pseudoscalar a decaying into two photons with the Belle II detector at the SuperKEKB collider. We search for the process e(+)e(-) -> gamma a, a -> gamma gamma in the mass range 0.2 < m(a) < 9.7 GeV/c(2) using data corresponding to an integrated luminosity of (445 +/- 3) pb(-1). Light pseudoscalars interacting predominantly with standard model gauge bosons (so-called axionlike particles or ALPs) are frequently postulated in extensions of the standard model. We find no evidence for ALPs and set 95% confidence level upper limits on the coupling strength g(a gamma gamma) of ALPs to photons at the level of 10(-3) GeV-1. The limits are the most restrictive to date for 0.2 < m(a) < 1 GeV/c(2). |
| Address |
[Polat, G.; Serrano, J.; Zani, L.] Aix Marseille Univ, CPPM, IN2P3, CNRS, F-13288 Marseille, France |
| Corporate Author |
|
Thesis |
|
| Publisher |
Amer Physical Soc |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0031-9007 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000577074900004 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4567 |
| Permanent link to this record |
| |
|
| |
| Author |
Belle II Collaboration (Abudinen, F. et al); Marinas, C. |
| Title |
Search for B+ -> K+nu(nu)over-bar Decays Using an Inclusive Tagging Method at Belle H |
Type |
Journal Article |
| Year |
2021 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
| Volume |
127 |
Issue |
18 |
Pages |
181802 - 10pp |
| Keywords |
|
| Abstract |
A search for the flavor-changing neutral-current decay B+ -> K+nu(nu) over bar is performed at the Belle II experiment at the SuperKEKB asymmetric energy electron-positron collider. The data sample corresponds to an integrated luminosity of 63 fb(-1) collected at the Upsilon(4S) resonance and a sample of 9 fb(-1) collected at an energy 60 MeV below the resonance. Because the measurable decay signature involves only a single charged kaon, a novel measurement approach is used that exploits not only the properties of the B+ -> K+nu(nu) over bar decay, but also the inclusive properties of the other B meson in the Upsilon(4S) -> B (B) over bar event, to suppress the background from other B meson decays and light-quark pair production. This inclusive tagging approach offers a higher signal efficiency compared to previous searches. No significant signal is observed. An upper limit on the branching fraction of B+ -> K+nu(nu) over bar of 4.1 x 10(-5) is set at the 90% confidence level. |
| Address |
[Lautenbach, K.; Polat, G.; Serrano, J.; Zani, L.] Aix Marseille Univ, CPPM, CNRS IN2P3, F-13288 Marseille, France |
| Corporate Author |
|
Thesis |
|
| Publisher |
Amer Physical Soc |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0031-9007 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000712526000010 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5020 |
| Permanent link to this record |
| |
|
| |
| Author |
Belle II Collaboration (Abudinen, F. et al); Marinas, C. |
| Title |
Precise Measurement of the D-0 and D+ Lifetimes at Belle II |
Type |
Journal Article |
| Year |
2021 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
| Volume |
127 |
Issue |
21 |
Pages |
211801 - 9pp |
| Keywords |
|
| Abstract |
We report a measurement of the D-0 and D+ lifetimes using D-0 -> K-pi(+) and D+ -> K-pi(+)pi(+) decays reconstructed in e(+)e(-) -> c (c) over bar data recorded by the Belle II experiment at the SuperKEKB asymmetric-energy e(+)e(-) collider. The data, collected at center-of-mass energies at or near the (sic)(4S) resonance, correspond to an integrated luminosity of 72 fb(-1). The results, (tau)(D-0) = 410.5 +/- 1.1 (stat) +/- 0.8(syst) fs and tau(D-0) = 1030.4 +/- 4.7 (stat) +/- 3.1 (syst) fs, are the most precise to date and are consistent with previous determinations. |
| Address |
[Lautenbach, K.; Polat, G.; Serrano, J.; Zani, L.] Aix Marseille Univ, CPPM, CNRS IN2P3, F-13288 Marseille, France |
| Corporate Author |
|
Thesis |
|
| Publisher |
Amer Physical Soc |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0031-9007 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000721613700003 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5032 |
| Permanent link to this record |
| |
|
| |
| Author |
Boronat, M.; Marinas, C.; Frey, A.; Garcia, I.; Schwenker, B.; Vos, M.; Wilk, F. |
| Title |
Physical Limitations to the Spatial Resolution of Solid-State Detectors |
Type |
Journal Article |
| Year |
2015 |
Publication |
IEEE Transactions on Nuclear Science |
Abbreviated Journal |
IEEE Trans. Nucl. Sci. |
| Volume |
62 |
Issue |
1 |
Pages |
381-386 |
| Keywords |
Charged particle tracking; silicon detectors; solid state devices |
| 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. |
| Address |
[Boronat, M.; Garcia, I.; Vos, M.] IFIC UVEG CSIC, E-46980 Valencia, Spain, Email: marcel.vos@ific.uv.es |
| Corporate Author |
|
Thesis |
|
| Publisher |
Ieee-Inst Electrical Electronics Engineers Inc |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0018-9499 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000349672900025 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
2140 |
| Permanent link to this record |
| |
|
| |
| Author |
Liptak, Z. et al; Marinas, C. |
| Title |
Measurements of beam backgrounds in SuperKEKB Phase 2 |
Type |
Journal Article |
| Year |
2022 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
| Volume |
1040 |
Issue |
|
Pages |
167168 - 19pp |
| Keywords |
|
| Abstract |
The high design luminosity of the SuperKEKB electron–positron collider will result in challenging levels of beam-induced backgrounds in the interaction region. Understanding and mitigating these backgrounds is critical to the success of the Belle II experiment. We report on the first background measurements performed after roll-in of the Belle II detector, a period known as SuperKEKB Phase 2, utilizing both the BEAST II system of dedicated background detectors and the Belle II detector itself. We also report on first revisions to the background simulation made in response to our findings. Backgrounds measured include contributions from synchrotron radiation, beam-gas, Touschek, and injection backgrounds. At the end of Phase 2, single-beam backgrounds originating from the 4 GeV positron Low Energy Ring (LER) agree reasonably well with simulation, while backgrounds from the 7 GeV electron High Energy Ring (HER) are approximately one order of magnitude higher than simulation. We extrapolate these backgrounds forward and conclude it is safe to install the Belle II vertex detector. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
|
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5496 |
| Permanent link to this record |
