Are there undiscovered heavy particles decaying to #Higgsbosons? #CMSPaper 1297 is an overview paper with all searches for Higgs boson resonances (as the Higgs boson can decay in many ways, there are also many signatures to examine). Such resonances would exist in scenarios with extra dimensions, more Higgs bosons, more W or Z bosons, and even if gravitons would exist and made at the LHC! We did not see any, so give constraints on what is still consistent with the data https://arxiv.org/abs/2403.16926
The frequency of simultaneous production of two Higgs bosons would allow us to directly measure the (Brout-Englert-)Higgs field at the LHC. We don't see it yet, and this specific #CMSPaper 1293 looks for it in the very common bbWW signature: https://arxiv.org/abs/2403.09430
There are a lot of composite particles containing b quarks, and their decay is interesting (the LHC even has a dedicated experiment to study them, @LHCbExperiment). But are there undiscovered particles (for example, extra undiscovered neutrinos) hiding in those B meson decays? #CMSPaper 1291 checks, and did not see any. https://arxiv.org/abs/2403.04584
The top quark is super heavy, and no one knows why. #CMSPaper 1289 is an overview of top quark measurements by the CMS experiment. It is also possible to measure that mass in many ways as a consistency check (that helps us understand it if those methods are all very different) https://arxiv.org/abs/2403.01313
#CMSPaper 1287 looks for undiscovered extra neutrinos, in signatures with many leptons (including taus, see plot, very few events). It is a #nullresult that sets very stringent bounds on heavy neutral leptons and majorana neutrinos https://buff.ly/3U7LYgZ
Quarks can only decay to other flavour quarks via W bosons. This #CMSPaper 1286 studies whether, very rarely, top quarks decay differently, specifically top quarks to two other quarks and a charged lepton. It sets the world's strongest constraints, improving our knowledge by three to six orders of magnitude 💪 https://arxiv.org/abs/2402.18461
#CMSpaper 1285: The LHC has the potential to make many particles, including some very frequent ones like the W boson. But what if these W bosons decay to undiscovered neutrinos? This result looks for those, specifically focusing on those sterile neutrinos leaving a signature in the CMS muon system https://arxiv.org/abs/2402.18658
#CMSpaper 1284 studies the cascade or Ξb particle, a particle that consists of a bottom, strange, and light (up or down)quark. Studying these composite quark systems, and particularly how they are stable/fall apart, teaches us more about the strong force https://buff.ly/443vyuI
Interpreting the LHC collisions is extremely data-intensive, and #CMSPaper 1282 describes how modern software techniques so our software (and #machinelearning) can run on many different platforms/processors and still efficiently and transparently reconstruct our collisions https://arxiv.org/abs/2402.15366
#CMSPaper 1278 looks at the #Higgsboson differently: Are there other particles that it decays to? In this case, there would be a more complicated Higgs field and more than one Higgs boson (so they can decay to each other then), for example, in two Higgs doublet models. Experimentally, we look for a four-particle resonance at the 125 Higgs mass that can decay to a combination of two muons, two taus, or two b quarks. There is nothing there, but there is not so much data yet https://arxiv.org/abs/2402.13358
#CMSPaper 1267: Other experiments (like LHCb) see #flavourAnomalies differences between leptons in (amongst other) decays of bound particles containing a b quark and other quarks. This paper measures the difference in those decays between decays of B mesons to Kaons and two leptons, R(K). The result is consistent with the standard model and discrepancies both, but with large uncertainties https://arxiv.org/abs/2401.07090
#CMSpaper 1261 sees a new way to produce a combination of known particles: a top quark, a W boson, and a Z boson. This is an important background to, for example, Higgs boson studies. The result sees evidence of 3.4 sigma for tWZ production: https://arxiv.org/abs/2312.11668
#CMSPaper 1255 measures the shape of the quark-gluon plasma blob created in LHC lead-lead collisions. Knowing that shape helps deduce the properties of the quark-gluon plasma, which have implications for astrophysics and even some aspects of string theory https://arxiv.org/abs/2311.11370
#CMSPaper 1259: are top quarks interacting inconsistently with other quarks in the weak nuclear interaction? Such a signature would be a tell-tale sign for new physics (and how often it happens would point to what kind of new undiscovered particles exist). In this case, we check interactions with photons and conclude if this happens, it is less than one in about 100000 top quarks. Paper: https://arxiv.org/abs/2312.08229
#CMSPaper 1257: are there top quarks that decay to three leptons? This would be a sign of physics beyond the standard model.
We don't see any (even when throwing machine learning at it to reduce background, just in case), at least its less than one in tens of millions of top quarks (depending on some assumptions). Paper: http://arxiv.org/abs/2312.03199#particlephysics#cern#physics#machinelearning@CMSexperiment
#CMSPaper 1248 studies collisions where the LHC works as a photon collider, and this paper searches for top quarks in those collisions to study top-photon interactions. None are seen(yet); these collisions should be a factor 1000 rarer than our sensitivity https://buff.ly/47m0IgW
#CMSPaper 1244 checks for #supersymmetry in events with photons and jets, looking for signatures without missing energy. With a focus on extra Higgs-like bosons in a hidden sector, the study found no additional events, even observing a slight undershoot https://buff.ly/45MRHN4
#CMSPaper 1247 reports the first-ever observation of two W bosons together with a photon. This could also be a sign of Higgs production together with a photon, but that is so rare that we don't see it (yet!) 😬 🫣
Find more information about this result here: https://arxiv.org/abs/2310.05164
#CMSPaper 1245: This paper studies if Υ bosons (made of a b quark-antiquark pair) get stopped differently in proton-lead as in lead-lead collisions. This is interesting because that is the case for particles made of c quarks. For the Y it is not, showing that very heavy quarks interact differently with very dense systems (like the quark-gluon-plasma) https://arxiv.org/abs/2310.03233
#CMSPaper 1228: one of the unexpected discoveries by CMS is correlations between the particles in proton-proton collisions, and this paper measures those in more detail by comparing short-range to long-range particle charges in various LHC collisions http://arxiv.org/abs/2307.11185
#CMSPaper 1230: This paper searches for undetectable particles in signatures with quarks, gluons, Higgs bosons and photons. It's a #NullResult, but it is sensitive to #supersymmetry partners of the Higgs boson, W/Z boson (worlds best!) ... and graviton! https://arxiv.org/abs/2307.16216
#CMSPaper 1238: The ongoing LHC data collection period, known as Run 3, will continue until the end of 2025 ⌛The @CMSexperiment already underwent substantial upgrades to be ready for Run 3🔧 This paper serves as a point of reference for the detector configuration during Run 3. 🤩 👉 https://arxiv.org/abs/2309.05466
#CMSpaper 1236: Question: How often does the actually LHC collide? The LHC intensity we call "luminosity". The @CMSexperiment has fancy detectors to check that. But there are also particles for which we can calculate their production rate so accurately that we can use them to calibrate the luminosity. This paper uses the production of the Z boson to measure the luminosity. The figure shows how well we measure the Z boson rate over time https://arxiv.org/abs/2309.01008
#CMSPaper 1234: #leptoquarks are hypothetical particles that interact with leptons and quarks, and they occur in many theories of physics beyond the standard model. This specific paper looks for leptoquarks in the (very) rare collisions where the LHC collides a lepton with a quark. This is a very novel method; it's not easy to select such collisions! It's a nullresult, but is so innovative that many improvements are still possible in the future.
#CMSPaper 1232: The production of Higgs bosons occurs in many ways, one of which is known as "vector-boson fusion," when the Large Hadron Collider produces Higgs bosons through the collision of W/Z bosons. Detecting these #Higgsbosons is challenging as the rest of the collision is particles produced close to the beam. Although a hint of the Higgs boson has been detected, it is too early to celebrate at just below 3 sigma. 🫣 🥳