e investigate the potential to search for semi-visible jets (SVJs) at the Large Hadron Collider (LHC) using initial-state radiation (ISR). Both photon ISR and jet ISR channels are considered, using a benchmark signal model with the decay of a leptophobic Z′ mediator forming two SVJs. We compare and extend several techniques to decompose the missing transverse momentum into per-jet...
The Hidden Valley scenario consists of a set of models where the Standard Model is accompanied by a Hidden Sector and connected with it via a heavy mediator or a weak coupling. If realised in nature, the Hidden Valley scenario may result in unusual and little-studied phenomena at the LHC. Under the assumption of a QCD-like confining dark sector, novel experimental signatures emerge,...
I will show how collider searches for long-lived particles (LLPs) can test the dynamics responsible for matter domination in the early universe. In particular I will focus on long-lived glueballs from a GeV-scale confining dark sector, of relevance for this workshop. After a summary of their cosmology, I will prove that searches of glueballs, from decays of the Higgs or other particles, test...
In this contribution, we will present our recent studies on the recasting of the different LHC darkQCD analyses using MadAnalysis5. The reinterpretation was done in the context of dark shower models focussing on semi-visible jet resonances.
We consider the prospect of the SM as a composite of a new fundamental fermionic sector ($q_{TC}$). Such scenarios can be considered as QCD-like, where the hadronization scale $\Lambda_{TC}\sim$ few TeV. The study of $q\bar q\rightarrow q_{TC}\bar q_{TC} $ at 100 TeV at FCC-hh has a direct analogue to the study of $e^+e^-\rightarrow q\bar q$ at around few GeV at LEP. While the latter...
Current search efforts for flavored dark sectors that couple to multiple SM quarks flavors has only included the coupling to isospin –½ SM quarks using the emerging jet signature. A natural extension to such models would be to change the coupling to isospin +½ SM quark. In particular, the coupling to SM top quarks allows for electroweak-like event selection and triggers to be used, opening...
The Higgs boson offers a unique portal to hidden sectors, enabling the study of Higgs-mediated dark showers (DS). These processes, characterized by multi-quark final states, present distinct yet elusive signatures due to their resemblance to QCD backgrounds. Using perturbative parton shower models, as detailed in recent theoretical benchmarks, we investigate DS phenomena initiated by the Higgs...
We present the new implementation of Dark Showers in the Herwig 7 generator. This implementation features for the first time an angular ordered dark shower and dark hadronisation implemented via the cluster hadronisation model. This talk will cover the scale hierarchies involved in dark shower models, and how to pick sensible values for generator parameters based on these scales. Secondly, the...
The pure-glue limit of confining dark sectors reveals new insights into dark shower phenomenology. When the dark quark masses and the scale of a collider's hard interactions that produce the dark sector are significantly larger than the dark confinement scale, there is a dark gluon shower that produces only dark glueballs. These glueballs can then decay to the Standard Model with lifetimes...
Dark showers arising from the Higgs coupling to a strongly confined dark
sector present a unique avenue for exploring new physics signatures.
Within the FCC-ee framework, this model is being studied,
highlighting the production of semi-visible jets (SVJs) enriched with
photons and leptons. These signatures, featuring displaced decays and
complex jet structures, demand tailored...
We demonstrate the sensitivity of the CMS search at the high luminosity LHC run for long-lived particles for Hidden Valley scenarios. We use a theoretically consistent parametrisation of the Hidden Valley parameters to establish our simulation setup. We also adopt a hybrid strategy and establish upper limits on the Hidden Valley production cross section as a function of the model parameters...
The creation of anti-nuclei in the Galaxy has been discussed as a possible signal of exotic production mechanisms such as primordial black hole evaporation or dark matter decay/annihilation in addition to the more conventional production from cosmic-ray interactions. Tentative observations of cosmic-ray andideuteron and antihelium by the AMS-02 collaboration have re-energized the quest to use...
With this talk, we would like to introduce the initiative for Dark Matter in Europe and beyond (iDMEu) and the ESCAPE Dark Matter Science Project. iDMEu is an initiative hosted by JENA (Joint ECFA, NuPECC and APPEC), and takes shape as a collective effort by a group of particle and astroparticle physicists to set up an online resource meta-repository, a common discussion platform and a series...
We present an ongoing effort to compare the new Herwig Dark Showers code with the existing Pythia Hidden Valley module. In addition to the physical parameters of the model, an event generator requires a number of semi-empirical settings to be tuned, particularly in the hadronisation. Since no dark showers have yet been observed, the best choices for these parameters can only be estimated using...
With this talk, we would like to introduce the idea of using the dark showers HepMC files produced in this effort as a test case to exercise the (distributed) computing machinery that would allow ATLAS and CMS to share HepMC files.
If this works and there are no drawbacks to implementation even for large-scale samples, there are the following benefits:
- ATLAS and CMS are able to...
With this talk, we would like to introduce the initiative for Dark Matter in Europe and beyond (iDMEu) and the ESCAPE Dark Matter Science Project. iDMEu is an initiative hosted by JENA (Joint ECFA, NuPECC and APPEC), and takes shape as a collective effort by a group of particle and astroparticle physicists to set up an online resource meta-repository, a common discussion platform and a series...
