A novel phenomenological approach to total charm cross section measurements at the LHC

Measuring the total charm cross section is important for the comparison to theoretical predictions of the highest precision available for charm today, which are completely known up to NNLO QCD for the total inclusive cross sections. These are also independent of charm fragmentation, while practical measurements of charm hadrons in a fiducial phase space are not. Recently the LHC experiments have reported non-universality of charm fragmentation, which shows that e.g. charm baryon-to-meson ratios are not universal in different collision systems, and that the related production fractions also depend on transverse momentum. This breaks the charm fragmentation universality that was assumed until recently for the extrapolation of experimental measurements to the full total charm cross section phase space. A proposal is made how to address this non-universality in a data driven way without the need to implement any particular non-universal fragmentation model. As a practical example, this method is applied to the extrapolation of published LHC measurements of $D^0$ production at $\sqrt{s}=5$ TeV to the corresponding total charm cross section, which fully accounts for charm fragmentation non-universality for the first time. The result, $8.43 ^{+1.05}_{-1.16}(\text{total})$ mb, differs substantially from the one assuming charm fragmentation universality, but still compares well to theoretical QCD predictions up to NNLO.Comment: to appear in Proceedings of the European Physical Society Conference on High Energy Physics (EPS-HEP2023

Finite element analysis-assisted surgical planning and evaluation of flap design in hand surgery

Given the anatomical variability among patients and the intricate geometry of the hand, the shape and size of the skin flap have traditionally relied heavily on the surgeon’s experience and subjective judgment. This dependence can lead to inconsistent and sometimes suboptimal results, particularly in complex cases such as web reconstruction in syndactyly surgery. Finite element analysis (FEA) provides a quantitative method to simulate and optimize skin flap design during surgery. However, existing FEA studies in this field are scattered across a wide range of seemingly unrelated topics. To address this, we present a comprehensive review focused on the application of FEA in skin flap design since 2000, with attention to all aspects of preprocessing and postprocessing. The primary objective is to evaluate the potential of FEA to generate patient-specific models by integrating individualized anatomical and biomechanical data while identifying key advancements, analyzing methodological challenges, exploring emerging technologies, and outlining future research directions. A critical finding is that the mechanical modeling of skin remains a major limitation in current FEA applications. To address this, future studies should focus on the development and refinement of non-invasive techniques for acquiring patient-specific skin properties. We also recommend several additional research directions based on our findings. These include exploring techniques to unfold 3D wound surfaces into 2D representations, which can improve mesh quality and computational efficiency; validating FEA simulations through large-scale, multicenter clinical studies to ensure robustness and generalizability; developing real-time AR/MR systems that integrate simulation or optimization results into surgical workflows; and creating AI-powered platforms that learn from clinical data to provide adaptive and personalized flap design recommendations. These findings offer a pathway to bridge the gap between simulation and clinical practice, ultimately aiming to improve surgical outcomes

Myeloid-Derived Suppressor Cells Are Controlled by Regulatory T Cells via TGF-β during Murine Colitis

Myeloid-derived suppressor cells (MDSCs) are well known regulators of regulatory T cells (Treg cells); however, the direct regulation of MDSCs by Treg cells has not been well characterized. We find that colitis caused by functional deficiency of Treg cells leads to altered expansion and reduced function of MDSCs. During differentiation of MDSCs in vitro from bone marrow cells, Treg cells enhanced MDSC function and controlled their differentiation through a mechanism involving transforming growth factor-β (TGF-β). TGF-β-deficient Treg cells were not able to regulate MDSC function in an experimentally induced model of colitis. Finally, we evaluated the therapeutic effect of TGF-β-mediated in-vitro-differentiated MDSCs on colitis. Adoptive transfer of MDSCs that differentiated with TGF-β led to better colitis prevention than the transfer of MDSCs that differentiated without TGF-β. Our results demonstrate an interaction between Treg cells and MDSCs that contributes to the regulation of MDSC proliferation and the acquisition of immunosuppressive functions

Observation of γγ → ττ in proton-proton collisions and limits on the anomalous electromagnetic moments of the τ lepton

The production of a pair of τ leptons via photon–photon fusion, γγ → ττ, is observed for the f irst time in proton–proton collisions, with a significance of 5.3 standard deviations. This observation is based on a data set recorded with the CMS detector at the LHC at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 138 fb−1. Events with a pair of τ leptons produced via photon–photon fusion are selected by requiring them to be back-to-back in the azimuthal direction and to have a minimum number of charged hadrons associated with their production vertex. The τ leptons are reconstructed in their leptonic and hadronic decay modes. The measured fiducial cross section of γγ → ττ is σfid obs = 12.4+3.8 −3.1 fb. Constraints are set on the contributions to the anomalous magnetic moment (aτ) and electric dipole moments (dτ) of the τ lepton originating from potential effects of new physics on the γττ vertex: aτ = 0.0009+0.0032 −0.0031 and |dτ| < 2.9×10−17ecm (95% confidence level), consistent with the standard model

Measurement of Charm Production in CMS and Total Charm Cross Section with Non-Universal Charm Fragmentation

This thesis presents differential and total charm cross section measurements at various center-of-mass energies in pp collisions. For the purpose of measuring the total charm cross section, the D$^{*+}$ differential cross sections are measured at $/sqrt{s}$ = 7, 0.9 and 13 TeV in the CMS detector by covering the largest possible phase space, resulting in the smallest extrapolation factor ever introduced at the LHC. The measured fiducial cross sections are extrapolated to the total cross section using a data-driven parametrization which is introduced for the first time to be applied to all the weakly-decaying ground states in pp collisions with non-universal charm fragmentation. Also adding other LHC measurements, the total charm-pair cross sections are measured at $/sqrt{s}$ = 0.9, 5, 7, and 13 TeV to be 1.83+0.35???0.37 , 8.43, .16 , 9.39 1.49 , and 17.43???2.57mb, respectively. These measurements supersede all the earlier LHC measurements which were derived under the fragmentation universality assumption, and show consistency with NNLO QCD theory predictions. The measurement of the total charm cross section as a function of the center-of-mass energy can be used to constrain QCD parameters. The very first exampleis shown to constrain the charm mass and the parton distribution functions particularly in the low-$x$ region

Measurement of Charm Production in CMS and Total Charm Cross Section with Non-Universal Charm Fragmentation

This thesis presents differential and total charm cross section measurements at various centerof-mass energies in pp collisions. For the purpose of measuring the total charm cross section,the D∗+ differential cross sections are measured at √s = 7, 0.9 and 13 TeV in the CMSdetector by covering the largest possible phase space, resulting in the smallest extrapolationfactor ever introduced at the LHC. The measured fiducial cross sections are extrapolated to thetotal cross section using a data-driven parametrization which is introduced for the first time tobe applied to all the weakly-decaying ground states in pp collisions with non-universal charmfragmentation. Also adding other LHC measurements, the total charm-pair cross sections aremeasured at √s = 0.9, 5, 7, and 13 TeV to be 1.83+0.35−0.37, 8.43+1.05−1.16, 9.39+1.35−1.49, and 17.43+2.10−2.57mb, respectively. These measurements supersede all the earlier LHC measurements which werederived under the fragmentation universality assumption, and show consistency with NNLOQCD theory predictions. The measurement of the total charm cross section as a function ofthe center-of-mass energy can be used to constrain QCD parameters. The very first exampleis shown to constrain the charm mass and the parton distribution functions particularly in thelow-x region

Measurement of the CMS offline tracking efficiencyfrom the ratio of reconstructed D∗ and D0 mesons

The efficiency for offline track reconstruction in CMS is measured directly from the data using a novel method. This method is based on taking the ratio of charm mesons reconstructed in the decay chains $D^{*\pm} \rightarrow K^{\mp}\pi^{\pm}\pi_s^{\pm}$ and $D^0 \rightarrow K^{\mp}\pi^{\pm}$, using the special kinematics of the so-called 'slow pion' $\pi_s$ from $D^*$ decay. It also requires the treatment of the a priori unknown mixture of prompt (from charm) and non-prompt (from beauty) contributions to the final states. Details of the method are explained and first results for the actual tracking efficiencies are presented

Heavy flavour production at CMS: D Meson Production, B Meson Production & Rare B Meson Decays to Two Muons

This talk presents recent results about heavy flavor production at CMS

A novel phenomenological approach to total charm cross section measurements at the LHC

Measuring the total charm cross section is important for the comparison to theoretical predictions of the highest precision available for charm today, which are completely known up to NNLO QCD for the total inclusive cross sections. These are also independent of charm fragmentation, while practical measurements of charm hadrons in a fiducial phase space are not. Recently the LHC experiments have reported non-universality of charm fragmentation, which shows that e.g. charm baryon-to-meson ratios are not universal in different collision systems, and that the related production fractions also depend on transverse momentum. This breaks the charm fragmentation universality that was assumed until recently for the extrapolation of experimental measurements to the full total charm cross section phase space. A proposal is made how to address this non-universality in a data driven way without the need to implement any particular non-universal fragmentation model. As a practical example, this method is applied to the extrapolation of published LHC measurements of $D^0$ production at $\sqrt{s}=5$ TeV to the corresponding total charm cross section, which fully accounts for charm fragmentation non-universality for the first time. The result, $8.43 ^{+1.05}_{-1.16}(\text{total})$ mb, differs substantially from the one assuming charm fragmentation universality, but still compares well to theoretical QCD predictions up to NNLO