LHCb, forward particle production, decays of the heavy hadrons and the detector upgrade

 

Financing source (agency):    Institute for Atomic Physics (IFA)

Project code:    PNCDI III, Module CERN-RO, Program 5, Subprogram 5.2; LHCb: contract no. 9/10.03.2020

Project director:    Dr. Florin MACIUC

Institutions:

E-mail: florin {dot} maciuc [at] cern < dot > ch

Research Team: see TEAM menu entry for a detailed overview of present and former members of the research team.

Most of the present project and the past projects activities are given in detail in the subchapter pages: Team, Research Topics, Service Tasks, Group Seminars, Conference Participation, Publications, Outreach, LHCb Upgrade, Research Facilities accessible from this main page.

Project Summary (as given in grant application)

Romanian participation in LHCb Collaboration started before 2000 and since then we witness the construction of LHCb single arm forward spectrometer, data taking in LHC’s 1st and 2nd RUNS with a LHCb instantaneous luminosity beyond initial expectation and with large impact on the field of High Energy Physics. Though the LHCb Romanian group is a young group, some members of the group have started working for LHCb Collaboration even as far back as 2005. Our work has spanned a very diverse task set, such as: data analysis, software development, LHCb construction followed by Upgrade, R&D tasks, generator tuning, outreach, and more. We propose a new LHCb project as extension of previous work and institutional responsibilities within LHCb collaboration. Some of the objectives follow from previous research studies and development tasks, other are new objectives of new research studies and R&D work. These are also new infrastructure sub-projects.

Our intention is to undertake flavor physics studies at LHCb thorough analysis of data from LHC RUN3 and collision generator studies. The newly proposed analysis includes Flavor Changing Neutral Current decay channels of beauty and charm decays with charmless final states containing at least a V0 particle. This work assumes a substantial effort to be dedicate to tracking studies, trigger implementation, optimization, and feasibly studies – the latter based on simulation sample and data-driven detector reconstruction efficiencies. Other flavor physics studies include strange baryon and meson production in proton-proton collisions at 13 TeV where we follow the publication procedure for a V0 analysis and a first draft for an analysis note of charged hyperon production Ξ and Ω. The flavor measurements and Minimum bias measurements of the team and of other LHCb groups will be implemented in HEPData database and in RIVET-framework analysis modules for usage in the tuning procedure of PYTHIA 8.2 collision generator.

We are about to finalize the Upgrade of LHCb detector, and by the end of 2020 we will finish the commissioning phase. Our group has already done excellent work on R&D tasks, aging studies, communication board development testing (PDMDB photon detector module digital board), assembly of RICH columns. We propose continuing the process of al 50 Photon Detector column assembly. We shall participate in the testing of columns and commissioning together with installation in LHCb cavern on the RICH mechanical frame. By the end of 2020 or even beginning of 2021 we expect to commission the fully Upgraded LHCb detector in time for first LHC beam runs. This work will involve shifts, early maintenance work, recalibration before and after first beam-on data. We intend to be member of the renewed RICH Memorandum, and deliver maintenance work and take shift assignments for RICH system. These will be deliverables during 2021. The work on R&D studies for LHCb second Upgrade continues in preparation for Framework TDR of LHCb second Upgrade which is scheduled to be send to LHCC by 2021. Our intention is to test commercial of the shelf solutions to communication and sensors of RICH system. The first tests were done in 2018 when we tested a potential control unit for a new digital board. We shall continue to look for optimal solution in case of these integrated circuits and will also started a work on sensor testing. The main focus during 2020 or 2021 will be to test the viability of these components and sensors in extreme radiation environment.

We should enhance the computing capabilities of the Ro-11 Grid site by increasing the computing power and providing adequate storage for data reprocessing. We also try to improve the existent IFIN infrastructure in terms of cooling, power delivery and optical-link speed. Outreach activities at Romanian high-schools and Universities will continue. New PhD students will be hired and trained starting with generator studies which allow us to introduce the physics behind flavor production and decay.

Objectives of the CERN Experiment (as given in grant application)

The LHCb collaboration proposed program is focused on heavy hadron decays with emphasis on: Charge-Parity-breaking transitions in beauty and charm decays, measurements of other decay parameters like CKM matrix elements, and study of rare decays like for example Flavor Changing Neutral Current Decays (FCNC). These topics are especially related to searches of New Physics or physics Beyond the Standard Model of Particle Physics (SM for Standard Model and BSM for the latter), which we hope to observed in the LHCb events of LHC Run 3 and RUN 4. Compared with other LHC experiments like ATLAS and CMS, our main goal is indirect evidence of New Physics, which could be inferred from: non-unitary CKM matrices, enhanced branching fraction of rare decays - decays with box or penguin diagrams at Leading Order in SM – relative to SM estimate, lepton universality tests, or other flavor-related observables.

Besides the CP, mixing and rare decay measurement program, LHCb has a strong interest in measurements of heavy hadron production, spectroscopy, and decays – the latter are connected to amplitude analysis or polarization and to decay branching ratios. Previous results of LHCb include new quantum states like tetra- and penta-quark systems, measurement of new exited stated in B, a doubly charmed baryon. We expect new results in these directions for the Upgrade LHCb spectrometer during next LHC runs.

Beyond SM searches for new and exotic particles and measurements of gauge boson production and decays are ongoing at LHCb. The particle jets are measured in forward direction and are corelated with gauge boson production or heavy flavor production. The particle production and cross-section measurement in proton-proton, ion-proton and ion-ion LHC collisions are established research fields at LHCb. In ion-ion and proton-ion collision events, the diffractive studies of central exclusive production (CEP) are an extension of previous LHCb results for proton-proton collisions. The CEP cross-section estimates of quarkonia production are done with or without veto at high rapidity from HeRSCheL detector used as an extension of LHCb detection capability.

The first LHCb Upgrade is done during this Long Shutdown (LS) of LHC and includes: a new Computing model, the upgrade of most sub-systems and a new upgraded trigger system. The RICH detectors are to be upgraded to 40 MHz acquisition rate with a photo-detection system based on Multianode-Photomultiplier Tubes (MaPMT). There is a full upgrade of tracking systems downstream and upstream of LHCb magnet, and the HCAL and ECAL systems will have an upgraded DAQ system and modified sensor gain to accommodate the higher collision rate. The R&D work for this first Upgrade is finalized, whereas annealing and aging studies continue in parallel with hardware and firmware debugging and installation.

A proposal of a further staged Upgrade was put forward by the collaboration, and includes a minor Upgrade of electronics and sensors during LS3, followed by a more ambitious full-Upgrade program during LS4 to take full advantage of High-Luminosity LHC (HL-LHC). The R&D work has already started and a comprehensive set of proposed measurement was included in a detailed physics case for this II-nd Upgrade.

Project Objectives (as given in application to IFA)

Chronologically, the first set of objectives are related to construction, testing and installation of RICH columns and electronics by the end of first semester of 2020. It is followed by the tedious process of commissioning, calibration and understanding of detector for the RUN3. The main objective is to have enough work-force at CERN to allow the installation and calibration of RICH photon-detector columns, and especially the communication boards (PDMDB – photon detector module digital board), and of the associated GBT plugins: TCM (Trigger and Control Module) and DTM (Data Transmission Module) boards. The installation and testing of columns are ongoing and we hope to get enough funds to support a Full Time Equivalent (FTE) work force at CERN over most 2020 for this activity. We expect additional work will be needed to maintain and operate the LHCb detector in 2021, work which includes subdetector shift, technical support, and recalibrations.

Related to previous work are the R&D objectives for a possible LHCb Upgrade II, and the small projects associated with the Ib Upgrade phase. The latter will be decided by the RICH operation during RUN3. The Upgrade II Framework TDR release was scheduled for early 2021, and we expect the sub-system TDR to follow. Our objectives include a new laboratory and a set of test boards for sensors and integrated circuits. We also hope to make a radiation hardness tests per year in 2020 and 2021 at proton and ion beam facilities in EU. A fist run was planned for next summer, early autumn.

Regarding the physics analyses we hope to get the LHCb approval for an Analysis Note by the beginning of 2020. The study includes measurements of V0 ratios, with KS and Λ production cross-sections in 13 TeV proton-proton collisions for LHCb acceptance and a generator bases extrapolation to full phase space. Our group prepares also the release a journal paper on a study of the production of quarkonia, with single mesons and double meson production studied separately. This generator study is done independently of collaboration though we use data from HEPData data-base including LHCb public measurements. The purpose is to use this generator optimization step to allow for a future LHCb Analysis. As already stated, we intend to implement a few LHCb trigger lines for RUN3 and RUN4 to study some rare decays like FCNC decays of b-hadrons with charmless decay. There will also be associated MC simulation studies to optimize the trigger lines and probe the feasibility in first and second upgrade phases assuming 50 fb-1 and 250 fb-1, respectively. Depending on the new PhD and Master student number we include also other generator studies, including some studies on strangeness production and decay with BSM contributions. We intend to pursue an aggressive publication strategy for both generator-production and tuning studies and also for R&D work. This includes several talks at dedicated conferences/workshops and schools and also few LHCb talks at international events. Another objective - in context of test board development and test bench design for sensors and integrated circuits – will be to initiate a patent request for one of the designs implemented by one of our PhD students and our engineers.

Other computing tasks and objective include an Upgrade of the group Ro-11 Tier 2 GRID site. We consider implementing an Upgrade to a Tier 2-D site with 400 TB storage as long term planning, depending on the development of required infrastructure. A more immediate Ro-11 cluster upgrade will consist in a refurbishment. It consists of replacing the old outdated machines by new more energy-efficient solutions which conform to the new WLCG and LHCb GRID requirements. The Outreach objective are participation to CERN and LHCb outreach events like EPOG Masterclasses in 2-3 sessions per year.

List of activities and subactivities for 2020-2021 (as stated in project proposal)

I. Upgrade of LHCb and publication of RUN2 measurements, trigger implementation for FCNC decays, generator studies, HEP computing and outreach:

I.1 assembly of 50 photon detector columns for RICN1 and RICH2, testing, installation and commissioning , calibration and commissioning;

I.2 R&D tasks for 2nd Upgrade;

I.3 physics analysis of RUN2 data and publication, trigger implementation, generator studies.


II. LHCb calibration and maintenance; trigger optimization; data-driven efficiency determination; tracking and Minimum Bias studies for new detector, publication of first data for RUN3; R&D studies:

II.1 R&D for Upgrade II, LHCb calibration and maintenance, aging studies;

II.2 Tuning of PYTHIA generator for forward -rapidity; trigger optimization for FCNC decays, first analysis of RUN3 data, tracking studies on new data and comparison;

II.3 Computing tasks for LHCb; HEPData and RIVET plugins; Outreach; cluster and Grid site Upgrade and refurbishment.