Chiral thermodynamics in a magnetic field

We study thermodynamic properties of the QCD vacuum in a magnetic field below chiral phase transition. The hadronic phase free energy in a constant homogeneous magnetic field is calculated in the framework of the chiral perturbation theory at non-zero pionic mass. It is demonstrated that the order parameter of the chiral phase transition remains constant provided temperature and magnetic field strength are related through obtained equation (the phenomenon of ''quark condensate freezing'').Comment: RevTeX4, 9 pages, no figure

Error estimates for pi-pi scattering threshold parameters in Chiral Perturbation Theory to two loops

Using the analysis of ChPT to two loops, we perform an error analysis of the threshold and low energy parameters, based on the uncertainties for the one loop low energy parameters and the resonance saturation mechanism. Different sets of one loop low energy constants have been considered.Thus, the predictive power of the effective field theory is quantified on the basis of the present experimental uncertainties.Comment: 12 pages, 2 tables, 3 figures. Numerics upgraded to v2 of ref.(8). New reference added. Typos corrected. New figure for SU(3) parameters include

Kirin: Hitting the Internet with Millions of Distributed IPv6 Announcements

The Internet is a critical resource in the day-to-day life of billions ofusers. To support the growing number of users and their increasing demands,operators have to continuously scale their network footprint -- e.g., byjoining Internet Exchange Points -- and adopt relevant technologies -- such asIPv6. IPv6, however, has a vastly larger address space compared to itspredecessor, which allows for new kinds of attacks on the Internet routinginfrastructure. In this paper, we present Kirin: a BGP attack that sources millions of IPv6routes and distributes them via thousands of sessions across various IXPs tooverflow the memory of border routers within thousands of remote ASes. Kirin'shighly distributed nature allows it to bypass traditional route-floodingdefense mechanisms, such as per-session prefix limits or route flap damping. Weanalyze the theoretical feasibility of the attack by formulating it as aInteger Linear Programming problem, test for practical hurdles by deploying theinfrastructure required to perform a small-scale Kirin attack using 4 IXPs, andvalidate our assumptions via BGP data analysis, real-world measurements, androuter testbed experiments. Despite its low deployment cost, we find Kirincapable of injecting lethal amounts of IPv6 routes in the routers of thousandsof ASes.<br

Refining the scalar and tensor contributions in τ→πππντ\tau\to \pi\pi\pi\nu_\tau decays

In this article we analyze the contribution from intermediate spin-0 and spin-2 resonances to the $\tau\to\nu \pi\pi\pi$ decay by means of a chiral invariant Lagrangian incorporating these mesons. In particular, we study the corresponding axial-vector form-factors. The advantage of this procedure with respect to previous analyses is that it incorporates chiral (and isospin) invariance and, hence, the partial conservation of the axial-vector current. This ensures the recovery of the right low-energy limit, described by chiral perturbation theory, and the transversality of the current in the chiral limit at all energies. Furthermore, the meson form-factors are further improved by requiring appropriate QCD high-energy conditions. We end up with a brief discussion on its implementation in the Tauola Monte Carlo and the prospects for future analyses of Belle's data.Comment: 32 pages, 13 figures. Extended discussion on the numerical importance of the tensor and scalar resonances and the parametrization of the scalar propagator. Version published in JHE

Entropy/IP: Uncovering Structure in IPv6 Addresses

In this paper, we introduce Entropy/IP: a system that discovers Internet address structure based on analyses of a subset of IPv6 addresses known to be active, i.e., training data, gleaned by readily available passive and active means. The system is completely automated and employs a combination of information-theoretic and machine learning techniques to probabilistically model IPv6 addresses. We present results showing that our system is effective in exposing structural characteristics of portions of the IPv6 Internet address space populated by active client, service, and router addresses. In addition to visualizing the address structure for exploration, the system uses its models to generate candidate target addresses for scanning. For each of 15 evaluated datasets, we train on 1K addresses and generate 1M candidates for scanning. We achieve some success in 14 datasets, finding up to 40% of the generated addresses to be active. In 11 of these datasets, we find active network identifiers (e.g., /64 prefixes or `subnets') not seen in training. Thus, we provide the first evidence that it is practical to discover subnets and hosts by scanning probabilistically selected areas of the IPv6 address space not known to contain active hosts a priori.Comment: Paper presented at the ACM IMC 2016 in Santa Monica, USA (https://dl.acm.org/citation.cfm?id=2987445). Live Demo site available at http://www.entropy-ip.com

Low temperature relations in QCD

In this talk I discuss the low temperature relations for the trace of the energy-momentum tensor in QCD with two and three quarks. It is shown that the temperature derivatives of the anomalous and normal (quark massive term) contributions to the trace of the energy-momentum tensor in QCD are equal to each other in the low temperature region. Leading corrections connected with $\pi\pi$-interactions and thermal excitations of $K$ and $\eta$ mesons are calculated.Comment: 10 pages, LaTeX2e. Talk given at 12th International Seminar on High-Energy Physics (QUARKS 2002), Novgorod, Russia, 1-7 Jun 200

A Longitudinal View at the Adoption of Multipath TCP

Multipath TCP (MPTCP) extends traditional TCP to enable simultaneous use ofmultiple connection endpoints at the source and destination. MPTCP has beenunder active development since its standardization in 2013, and more recentlyin February 2020, MPTCP was upstreamed to the Linux kernel. In this paper, weprovide an in-depth analysis of MPTCPv0 in the Internet and the first analysisof MPTCPv1 to date. We probe the entire IPv4 address space and an IPv6 hitlistto detect MPTCP-enabled systems operational on port 80 and 443. Our scansreveal a steady increase in MPTCPv0-capable IPs, reaching 13k+ on IPv4(2$\times$ increase in one year) and 1k on IPv6 (40$\times$ increase). MPTCPv1deployment is comparatively low with $\approx$100 supporting hosts in IPv4 andIPv6, most of which belong to Apple. We also discover a substantial share ofseemingly MPTCP-capable hosts, an artifact of middleboxes mirroring TCPoptions. We conduct targeted HTTP(S) measurements towards select hosts and findthat middleboxes can aggressively impact the perceived quality of applicationsutilizing MPTCP. Finally, we analyze two complementary traffic traces fromCAIDA and MAWI to shed light on the real-world usage of MPTCP. We find thatwhile MPTCP usage has increased by a factor of 20 over the past few years, itstraffic share is still quite low.<br

Spectral functions of isoscalar scalar and isovector electromagnetic form factors of the nucleon at two-loop order

We calculate the imaginary parts of the isoscalar scalar and isovector electromagnetic form factors of the nucleon up to two-loop order in chiral perturbation theory. Particular attention is paid on the correct behavior of Im $\sigma_N(t)$ and Im $G_{E,M}^V(t)$ at the two-pion threshold $t_0=4 m_\pi^2$ in connection with the non-relativistic 1/M-expansion. We recover the well-known strong enhancement near threshold originating from the nearby anomalous singularity at $t_c = 4m_\pi^2-m_\pi^4/M^2 = 3.98 m_\pi^2$. In the case of the scalar spectral function Im $\sigma_N(t)$ one finds a significant improvement in comparison to the lowest order one-loop result. Higher order $\pi\pi$-rescattering effects are however still necessary to close a remaining 20%-gap to the empirical scalar spectral function. The isovector electric and magnetic spectral functions Im $G_{E,M}^V(t)$ get additionally enhanced near threshold by the two-pion-loop contributions. After supplementing their two-loop results by a phenomenological $\rho$-meson exchange term one can reproduce the empirical isovector electric and magnetic spectral functions fairly well.Comment: 10 pages, 6 figures, submitted to Physical Review