Progress in two-loop electroweak corrections to gg -> HH and gg -> gH

In these proceedings, we summarise our recent calculations of next-to-leading order electroweak corrections to Higgs boson pair and Higgs boson plus jet production. The calculations are divided into different regions. In the high-energy region, we analytically calculate the Higgs boson contribution to the leading two-loop Yukawa corrections for $gg\to HH$. These corrections are generated by a single virtual Higgs boson exchange within the top quark loop. Our high-energy expansion yields precise predictions for the region where the Higgs boson transverse momenta $p_T > 120$ GeV. In the low-energy region, we compute the complete two-loop electroweak corrections to $gg\to HH$ and $gg \to gH$. We obtain analytic results through the large top quark mass expansion, covering all sectors of the Standard Model.Comment: Contribution to the proceedings of the European Physical Society Conference on High Energy Physics (EPS-HEP2023), 21-25 August 2023, Hamburg, German

Exploring engagement in vlogs through content, context and presence

In this thesis, we present a qualitative exploration of how video bloggers (vloggers) achieve audience engagement in their vlogging. Engagement is a crucial factor for developing relationships between content providers and consumers, and for the quality of consumers’ experience with media products such as online videos. Previous research in marketing and media studies suggests that achieving engagement with their audience is significant for the success of vloggers’ careers, such as obtaining large fan bases on YouTube and other social media sites. However, how vloggers achieve engagement is rarely explored, and their audience engagement has rarely been clearly defined. We view vlog audience engagement as having two facets: consumer engagement and media engagement. This thesis applies theories of both customer and media engagement to the exploration of vlog consumption. By investigating three factors of vlogs — content, context, and presence — we address the question of how vloggers achieve audience engagement. We argue these three elements to be key to constructing audience engagement. We employ a case study research with a qualitative content analysis method applied to video samples from four well-known YouTube vloggers. Our results suggest that vlog audience engagement can be addressed through both customer and media engagement theories, which can help to account for vlogger-audience relationships beyond video consumption and audience experience during video viewing. To obtain consumer engagement, vloggers can use interaction, self-presentation, information management, and rewards in their vlog content. Vloggers’ execution of these engagement factors in their content can also be conditioned by the vlogging context, namely the context of vlogger, audience, physical environment, social environment, and medium. Furthermore, sensory and social elements may evoke aspects of presence to contribute to media engagement. Sensory elements are colour, camera usage, image quality, and audio quality; social elements are the vlogger’s eye contact, facial expressions, conversations and gestures. By applying both customer and media engagement theories to explore vlog audience engagement, this thesis bridges gaps regarding the application of engagement theories explicitly to vlogging. It indicates that vlogs are a useful medium to encourage audience engagement both inside and beyond vlog consumption. Our results suggest that customer engagement factors can be added to vlog content to encourage vlogger-audience connections beyond video consumption. We also indicate that context can influence the production of related customer engagement factors in vlog content. Using presence determinants in video production may affect vlog viewers’ direct consumption experience for media engagement. This thesis provides a way to substantially understand vlog audience engagement by considering both viewers’ video consumption experiences and the building of vlogger-audience relationships. The thesis also offers new directions for researchers to explore audience experience with vloggers from an engagement perspective through vlog content, context, and presence. Furthermore, our results could also be developed into practical guides in the future for new or existing vloggers to build and maintain connections with their audience and improve the latter’s video consumption experience

Towards ruling out the charged Higgs interpretation of the RD(∗){R}_{D^{\left(\ast \right)}} anomaly

Motivated by the notorious anomaly in the lepton flavor universality ratios RD(∗), we study the sensitivity of the Large Hadron Collider (LHC) to a low-mass charged Higgs boson H− lighter than 400 GeV in a generic two Higgs doublet model. A combination of current constraints from the Bc → τν decay, Bs meson mixing data, tau sleptons and di-jet searches at the LHC allows to explain the RD(∗) anomaly at the 1σ level by a low-mass charged Higgs. In this context, we estimate the reach of an LHC search for resonant H− production, where the final state contains an energetic τ lepton decaying hadronically, a neutrino with large transverse momentum, and an additional b-jet (pp → b + τh + ν). Requiring the additional b-tagged jet in the τν resonance search profits from the suppression of the Standard Model background, and therefore it allows us to judge the low-mass H− interpretation of the RD(∗) anomaly. To demonstrate this, we perform a fast collider simulation for the τν resonance search with an additional b-tagged jet, and find that most of the interesting parameter region of the whole mass range can already be probed with the current integrated luminosity of 139 fb−1

Rational Terms of UV Origin at Two Loops

The advent of efficient numerical algorithms for the construction of one-loop amplitudes has played a crucial role in the automation of NLO calculations, and the development of similar algorithms at two loops is a natural strategy for NNLO automation. Within a numerical framework the numerator of loop integrals is usually constructed in four dimensions, and the missing rational terms, which arise from the interplay of the $(D-4)$-dimensional parts of the loop numerator with $1/(D-4)$ poles in $D$ dimensions, are reconstructed separately. At one loop, such rational terms arise only from UV divergences and can be restored through process-independent local counterterms. In this paper we investigate the behaviour of rational terms of UV origin at two loops. The main result is a general formula that combines the subtraction of UV poles with the reconstruction of the associated rational parts at two loops. This formula has the same structure as the R-operation, and all poles and rational parts are described through a finite set of process-independent local counterterms. We also present a general formula for the calculation of all relevant two-loop rational counterterms in any renormalisable theory based on one-scale tadpole integrals. As a first application, we derive the full set of two-loop rational counterterms for QED in the $R_{\xi}$-gauge.Comment: v2: Normalisation of MSbar poles clarified; v3: Version published on JHEP; References added; Further comments on use of master formula (5.61) in Sect. 6; New footnote on scale dependence in Sect. 5; Typos fixed and/or presentation improved in eqs. (4.8), (4.20), (5.2), (6.5), (6.7), (6.8), (A.2), (A.4); Results unchange

Next-to-leading order electroweak corrections to gg → HH and gg → gH in the large-mt limit

We compute two-loop electroweak corrections to Higgs boson pair and Higgs plus jet production, taking into account all sectors of the Standard Model. All diagrams with virtual top quarks are computed in an expansion for large top quark mass up to order 1/$${m}_t^8$$ or more. We present analytic results for the form factors and discuss the convergence properties. For the process gg → gH we also consider QCD corrections in the large-m$_{t}$ limit

Next-to-leading order electroweak corrections to gg → HH and gg → gH in the large-mt limit

We compute two-loop electroweak corrections to Higgs boson pair and Higgs plus jet production, taking into account all sectors of the Standard Model. All diagrams with virtual top quarks are computed in an expansion for large top quark mass up to order $1/m^8_t$ or more. We present analytic results for the form factors and discuss the convergence properties. For the process $gg → gH$ we also consider QCD corrections in the large-$m_t$ limit